There is no “hidden” gene here. The gene you are asking about is now generally referred to as either “het Platty” or “het Daddy” and it is just the weakest member of the het BluEL group. A PlattyDaddy is basically the same as, say, a Lesser x Mojave, it is just that the “het Daddy” allele is so weak that it does not cause an extreme phenotype change. The het Daddy seems to be a phenotypically WT animal thought there may be some very subtle markers
All the answers and animals you seek can be found on Ralph’s birthing records but here are the highlights:
I do not recall the first time he did it but years ago Ralph did Platty x Platty and only got one egg and what came out was a normal looking animal. He repeated it this year (Clutch 11) and got a SuperLesser a couple Plattys and three or four normal looking animals. These normals are SuperDaddy. If you were to breed one of these to a SuperLesser you would get all Platty.
There are numerous clutches where he bred het Daddy to Butter and produced ButterDaddys real quick, you can find one in Clutch 3 from 2010