Yep, that second last photo looks best of him. Lower tail, more straight line from legs, breast, on through neck.
If you want to get the gray color going in your birds but have no grays around your best bet is to get some pure blacks. Now, I don't know the chances with Shamos, but in most other breeds, pure solid black and/or blue almost always carry the silver gene, what makes grays, and crossing it into whatever desired color once, then working it from there on helps. Black hen x other color cock = black hens, black cocks w/gray (silver and red) leakage Take that offspring male and breed him to more "other color" birds and you'll continue to get the gray/silver color going.
Assuming you mean gray as in golden or silver wheaten/duckwing.
If you want to get the gray color going in your birds but have no grays around your best bet is to get some pure blacks. Now, I don't know the chances with Shamos, but in most other breeds, pure solid black and/or blue almost always carry the silver gene, what makes grays, and crossing it into whatever desired color once, then working it from there on helps. Black hen x other color cock = black hens, black cocks w/gray (silver and red) leakage Take that offspring male and breed him to more "other color" birds and you'll continue to get the gray/silver color going.
Assuming you mean gray as in golden or silver wheaten/duckwing.