Yeah, the 1" up from centre is pretty standard, but there's plenty of leaway to make 'em how you like.
What I don't like is excessive handle length effectively sortening the lower limb.
Especially on short selfbows, I like to use the fade as the bottom of the grip, this can save you an inch or so of nonworking limb.
I don't like the whole plank with a little bendy bit on the end look, like those fancy modern take downs with cast alloy risers... what's that all about?
I find the grips on my bows are generally getting sorter with every one I build.
Del