I love working with hackberry, even more then osage (I can hear all the people crying "HERETIC" already).
If the wood is a little bit damp, go ahead and steam away. If it has had plenty of time to cure out, try the dry heat. With your 30" draw length, I would recommend going a little over the usual double the draw length plus 10%. That would give you a 66 inch bow (30 + 30 + 6). Go to 69", that gives you another 15% over the double your draw length. I bet if you get this thing tillered carefully and the m,oisture content down below 8% you will get virtually no string follow.
If you are using a draw knife or spokeshave on the belly, make sure it is razor sharp. Then sharpen it better. Once it is better than razor sharp, take it to a professional and get it sharp enough to etch your initials in glass. Hackberry can have some mean hidden grain reversal. A dull tool will cause tear-outs that a really sharp tool can sometimes avoid.
Hackberry doesn't take stain really well for me, but the wood looks great with just an oil finish rubbed in. I back mine with rawhide that I have pre-died or stained. The dark rawhide really sets off the creamy pale yellow color of the wood. Take lotsa pictures and post often.