With a 56# bow, you can pretty much pick whatever you want to use for deer. They are not especially difficult to penetrate. I shot through one with 125 grain snuffers from my 55# longbow. I'm thinking of trying 160s this fall. Last year I shot Delta 2 blades from my 46# Kanati, and I can tell you they go through a whitetail VERY quickly! Terry Green shoots most everything with 4 blade Deltas.
Just pick what you like and can sharpen and go kill deer. Zwickey Deltas have been used on every critter on the planet with great success. I don't see why they wouldn't work for you.