I just completed my first ASL build this spring, and have been collecting a few here and there from other builders, just to compare bowyer styles. I have found that I draw my ASLs about 1.5" shorter than my R/D bow. My bow arm is bent more, but solid at full draw, and my upper body feels more compact....sounds wierd, but that is the feel...a more relaxed style of shooting, more natural, flowing form.
My bow was made 68" long, straight limbed, with a deeper than average slight wedge grip, that measures 2 1/4". My draw on my R/D is a good 28", but with a heavier # ASL, more like 26.5".
With a draw that long, I would bet 70" would be pretty good for you.
Look into some photos of Howard shooting, and compare to your form with an R/D bow, and I bet your draw will reduce a bit.