far to many birds in both:-
Race loft 6' x 6', if for youngbirds then prob 25-30max if oldbirds you could fit 8 widowhood boxes across the back wall which would accomodate 8 pairs in comfort.
Stock loft 6' x 6', again you can fit 8 good sized boxes but 6 pairs would be more comfortable.
In both the above the more space the birds have the happier they will be in there environment, a lot of youngbird fly aways are due to overcrowding. Put 30 yb's in a section with 30 perches and you'll lose 10 of them, put 20 birds in a section with 30 perches and you are unlikely to lose any in flyaways.