If you want to talk about average draw length then it's closer to 28" and not 29.5".

Answering the OP's question about whether to shoot a speed bow at 60# or smooth cam at 70#? I've done a few tests of my own on this, although not scientifically. Just using a chrono, and with bows set to my draw length, but both shooting the same arrow. I can't shoot 70# so I'll just tell my experience.

Bow #1--Martin Moab--smooth cam bow set to 27" draw (measured) and 49#.

Bow #2--Martin FireCat--hard cam bow set to 27" draw (measured) and 42#.

Both bows shot a given arrow at the same speed. These are almost identical bows except for the cams. The FireCat shot the same arrow at the same speed although drawing 7# less weight. That difference made that harder cam seem a lot smoother. The arrow weighed 275gr.

I know this doesn't come near the 60# or 70# scenerio, but it should give some approximation of what to expect. Me? I'll take the lower draw weight every time.

thanks i'll give that a try

Some rules I go by
 

Every bow is slower than a 30/06. Live with it.

Measure speed by yourself by shooting practice. Get the drop-off of shots every ten yards. Get it for one bow, unless you like getting ten different bows, for your pocketbook.

Practice and get as pin-point accurate as you can. Speed won't help, if you can't hit the broadside of a barn.