My first frame will be made without a frame jig or an alignment table. What should I look for in a used straight edge? Would more than one length be helpful? It seems like I need 36 inches to go across the BB to the HT. Should I look for one that is ruled? How about stainless vs hardened steel vs aluminum (vs just a stainless ruler)? What would you use if you had no jig and no table? I've got plenty of time to wait for the "right" one to come along.