i did pretty much the same as deftones did
except i used a small plate to get the curve.
i have to ask why you want to use steam on such a hygroscopic wood?
i just use a heat gun when i bend in curves.not sayibg that you cant use steam,but you will have to wait a couple of weeks for the moisture to
disapate again from the wood.with a heat gun you just wait a day or two for the wood to rehydrate some
you will also want to use sone kind of strap on the belly side of the limb when making the curve,this helps keeps splinters down when bending the wood
also keep in mind if your tips are narrowed already,you may end up with some tip alignment issues after putting the curves in.
i try and leave the tips plenty wide untill after curving,this allows room to help get tips aligned and the string aligned down center
good luck