I am going to start on two more bows (#'s 3 and 4) and have a couple of questions.  I have two boards 2.5x72" with pretty good grain running the length, and the growth rings have the thicker bands I have read are better.  They will be for my wife and younger daughter.  I plan to make one of them 66 tip to tip, and one of them 72 ttt.  My goal weight for them will be 35-40#.  I want them fast enough to shoot, but not too strong for them since they will be exclusively for backyard fun.
I am keeping them long enough to give me room for error since I am still getting the feel for making bows.  Any concern with the lengths?
I have read about the layout on pyramid bows being best if it goes to a point from the fades, and then having the last 4-6" parallel to give the tips some strength.  Is there any real advantage to that compared to just drawing from fades to 3/8" tips?  I plan to use a tillering gizmo - I don't know if it has a real name - to get a circular tiller.  I don't expect it to give good tiller just because it goes to a point.  Since I am tillering anyway, does it make much difference?
I know pyramids bows are simple and a good starting point, and maybe I am over thinking it, but I would like to have the best chance at having them work and not blowing up a lot as I learn if it can be avoided.