Just one thought re. bonuses and game balance.....

You can already get +1 valor anything-that-is-mounted just by building up the horse farms to the max - and you can do it without building up your castle tech. (I mean, the only prereq is 20% farms.)

I don't know how this may fit with your plans - but I know if I get a region that gives me +1 valor for say hobilars or szekely, then I'm going to build up my horse farmers there and turn them into v+2 without much trouble.

Best,