ultimatly the material and process you choose are functions of the radius you want to achieve. Birch ply can turn a 6" safely without splitting. Steam, depends on the material, choose something porus. Bending ply (wacky wood) can turn 3" easily. Any tighter than that, use veneer. I suggest the paper backed kind - makes it lots easier to manipulate and gives more glue options.
for a small form you can actually take foam to a hot wire and make a simple jig, I’ve seen students even make male/female (compound curves) jigs out of blue foam and get good results.