I'm another strong Torges-style bow advocate. I always make the bottom limb shorter to perfectly balance the bow on my middle finger. This also puts the bows geographical center, handle center, and string fulcrum points in very close and balanced relation with one another... much more-so than with those whose handle and bow center are at the exact same place.
I make all of my bows with radiused bellies, whether they're made from osage, yew, hophornbeam, hickory, ash, elm, cherry, etc. and regardless of whether they're selfbows, backed bows, trilams, or whatever. Whether or not a bow's belly is flat or radiused isn't as critical as its other design characteristics and how all aspects are coordinated.