DC, have you tried steaming the handle and bending it that way? I've tried on a couple different woods and they didn't budge, but it could work if you are working with wood that responds well to steam. Where do you plan to steam and implement the deflex?
Funny thing, I currently just add deflex at glue up and have a slight bend through the handle, but I find I'm not getting enough so on my next build I'm going to try splicing billets (So I'm doing the opposite of what you want to do). I would think you take more advantage of the deflex when you splice as the deflex is unstressed coming right out of the handle, but I'll confirm this after I get a few spliced deflexed bows under my belt.