Danehill X Danehill Below is an article published Thursday 7th November 2013 it read                      
 "Trio of Gr1 winners debunks prevailing anti-Danehill double cross sentiment.  Pedigree analyst and statistician, Renée Geelen, discovers that despite the popularly held view that Danehill over Danehill is a pedigree mistake, there might be more positives to the cross than originally thought. One Thousand Guineas star Guelph is the current pin-up girl for inbreeding to Danehill - being by Danehill's son Exceed and Excel from a daughter of a Danehill mare - but is she an exception or she is the start of a trend that breeders should be pursuing? Much of the talk about Danehill lately has been the need to find an outcross sire to him that will be the next big thing.  History tells us that sire lines eventually fade and another will rise to take its place.   Danehill's last southern hemisphere crop was born in 2003/04, and his big-name sire sons are now coming into the latter half of their stud careers, which gives context to this discussion. When a horse is so influential, should we be trying to avoid him?   If he is the best, surely the goal should be to get more of the best?  Many breeders are already thinking along these lines, and the numbers are starting to become significant.   Danehill has now had just over 1,000 named foals inbred to him, and 16 stakes winners highlighted by 3 Gr1 winners.  They are Guelph, Astaire (who won the Gr1 Middle Park Stakes in England during October) and NZ's Southern Lord (Gr1 Levin Classic).   The percentage of SW’s to named foals is quite low, (slightly less than the population average), but what really stands out to me in perusing the list of SW’s bred this way is how many of them are young horses that are still improving.   Therefore, it is a natural assumption to expect that the statistics will improve with time.
Back in 2010, when Guelph was born, Byron Rogers of Performance Genetics LLC told "Danehill was as sound as they come and his horses have a lot of qualities that trainer’s like in horses (they sleep, eat and run fast!) This makes him a fantastic stallion to inbreed to. There are not a lot of holes in Danehill if you are looking to him as a subject to inbreeding to in the hope of increasing your chances." That pretty well sums up why people love Danehill and why breeders have been taking the punt on inbreeding to Him. Pulford also acknowledges, “The sex-balancing of the Danehill cross was also a factor, as many line-breeding analysts would tell you that it works best that way".
Then I read the article in The Informant dated 21-08-2015 stating
. Re the new stallion standing Pure Champion  which stated: “Obviously Danehill male line sires will suit him, especially Redoute’s Choice’s sons, and breeders need have no fear of inbreeding here, as I can think of no safer vehicle to which inbreeding could be made.”
Plus on the 5th of March 2018 in the ANZ Bloodstock News
Double Danehill gains momentum due to Seabrook becoming the 85th Stakes-winner and the 8th 2yo winner this year,

My answer to these 3 articles is the figures don’t stake up to these statements
Returning to the first article it stated statistics will improve in time, yet over 8  years later, on the double up, they are getting worse, the numbers are increasing rapidly with just 22 more group one winners and a lot of these matings are to very commercial stallions,
there were as stated in the article 3 x Gr1 winners, they are:
Southern Lord2009 Colt 3M x 3F to Danehill, also 5M x 5F to Wilkes and his sire Court Martial is balanced by an independent female line in Goofed, therefore this is what made this horse, not the Danehill.                  
Guelph2010 Filly, 2M x 3F Danehill yet Danehill carries His Majesty and Guelph’s dam carries Graustark, the full brother. The linebreeding that is working, in this case, is 4F x 6F x 5F, to the full brothers.
Astaire2011 Colt, 3M x3F to Danehill, added to this pedigree is Kahyasi4F x 4F,  Roberto 5F x 6F and with the sire Intense Focus being line-bred to
 Blushing Groom 5Mx 6F and the dam of Astaire bringing in a further line of Blushing Groom 6F.

The other ones include
The Mission, 2014 Colt 3M x 3M to Danehill, the Winner At 2 of the G.1 ATC Champagne Stakes Has as the 2nd Grandsire Danehill and More Than Ready as his Second Dam sire, Danehill's grandsire Northern Dancer is balanced through a daughter in the dam via More Than Ready,
Alizee 2014 Filly, 3F x 3M to Danehill, she has the filly factor Daughters of Marscay 4F x 5F to the powerful dam line, So this would be more effective.
Prompt Response 2013 Filly, 3M x 3M to Danehill, she also has the mare Make Plans on the powerful dam line and in the sire, she is the dam of the sire Monde Bleu both in the 5th generation, this makes more sense to me.
Luger 2010 Colt 3M x 3M to Danehill which carries the female line of Alibhai and the mare brings in a son, plus this pedigree has balanced lines of Native Dancer and Nasrullah
 unlike the other 7 listed above which are inbred 3 x 3 or in the case of Guelph 2 x 3 
Danzdanzdance Dual G1 winner December 2018 has Danehill 3M x 3M she is a filly who also has 2 daughters of Tudor Minstrel 7Fx7F.and Crafty Admiral 7M,7F x 7M
Farnan has Wilkes 5M x 6F , Beat The Clock Intentionally 6M x 6F, Campanelle Sharpen up 4M x 5F ,Subjectivist Sadlers wells 3M x 4F Sword of State Northern Dancer 6M.6M x 7F.6M, Captivant Marscay 5F x 4M Even So Count Fleet 7F x 7F Tigertanaka Bold Ruler 7F x 7M Wellington Mr Prospector 5F x 5M Amphitrite Buckpasser and Sir Ivor 6F x 6F

Therefore research shows me as you can see, other linebreeding made these horses and I doubt if Danehill made a little contribution if at all in most of these pedigrees above.

To summarize 25 group one winners and 137 group winners, these are very poor figures 1.0% when you see the double up of Danehill has now reached as per Arion Pedigrees 13474 named foals for 9643 runners that is a loss of nearly 4,000 that did not make the racetrack.

I would not recommend a mating on the double up of Danehill unless you have other double-ups of the correct ancestor's in the right generations to get a good horse. 

NZ Premier, Select and Festival Sales 2015 In these sales catalogue's there were 27 horses with Double Danehill, five Premier lots, fourteen Select lots and eight in the Festival sale,
11 of these were not sexed balanced and 20 of the 27 were inbred 3 x3 or closer
16-1-2019 Now they are  5 years old, 2 were withdrawn, they are not named, a further 10 did not make their reserve of $640,000 in total, this was a very high pass rate compared to the sale average, of the 15 left they sold for $444,000, none of them sold for above the average of the relevant sales,
 the total of the 27 horses have of today won a total of $503,000
I believe the above shows that breeding this way does not present a good horse at the sales.

Don't get me wrong as soon as we start line-breeding  4x4 instead of inbreeding 3x3 or closer it may be a different story, time will tell, of the 488 stallions I list as standing in Australasia there are 234 or 48% with Danehill in their pedigree, however now of these, 86 are in the 4th generation so using these sires you would not create in-breeding.