I didn’t describe it here, as they aren’t stonefruit, but, since you asked 
I planted 3 types (6 seedlings total):
1.) Goldrush x Hudson’s Golden Gem- This takes a great flavorful apple (Goldrush) and mixes it with a very large tasty (sweet) apple.
2.) Goldrush seedling- one of my favorites and a great keeper
3.) Golden Russet Seedling- absolute favorite apple
All 3 of the above can get over 20 brix, so I suppose I’m mostly going for sugar/flavor. Each of them is also scab resistant/immune, so hopefully disease resistance would be good.
I’ve been thinking about what to breed next year and Sweet Sixteen, Pitmaston Pineapple, Scarlet O’Hara, and Ashmead’s Kernel are all worth considering.
Edit: I should also mention that the crosses I made this spring didn’t take (either bad pollination timing or I lost the apple to bugs or critters). I did plant a dozen+ seeds a bit over a week ago from Scarlet O’Hara and Pitmaston Pineapple.