Here are the handles I like on my bows. They are called a bulbous type of handle. You can see that they are thicker than the limbs. I prefer for my limbs to bend right up to the handle but not always.
In my opinion you shouldn't shape your handle until the tillering is done. There is no need to and by leaving it bulky you have a place to clamp your bow while you are reducing and tillering the limbs. After you have the limbs tillered and you are at the desired weight then you can shape your handle to suit yourself and you shouldn't have to worry about the handle bending...unless you want a bendy handled bow.
If you are dealing with a board bow with a glued on riser you want to start off with the full thickness board(approx 3/4" thick), add the handle riser and then begin reducing the limbs. In the end, you want the riser sitting above the plane of the limb belly. That way the handle area won't bend and the riser will stay in place without popping off.