Thanks everyone, and Eric and Dane- you both are very right. I once tried to draw two small bows together a year or two ago, didn't work, couldn't shoot for two weeks- and my shoulder ached every morning for a month. I am by no means invincible, but the design of this bows allow me to shoot the heavier weight at the cost of cast at a distance. Besides, I can't shoot very long, and when i get tired, I stop.
My next bow will be 70" long, elliptical tiller, 70# at 27", 1 1/2" wide for most of the legnth, except the last 8" at the tips. 1 1/4" thick at the handel tapering to 1/2" tips.