Ok as said, the hitcap is 17%.
A shadowpriest/moonkin provides 3%
A draenei in your GROUP (not raid) provides 1%
Suppression can provide 3%
I advise you aim for 11% hit (10% if you're alliance) and supression, or 14% (13% alliance) without the talent and 2 spellpower/crit trinkets. Try to get one of the +hit trinkets (list
here, violet hold and triumph badges ones are the easiest to get), and equip a hit trinket when you don't have a spriest/boomkin, so you don't have to worry about complicated gear swapping or being over the hitcap and wasting dps stats.