Kent you sound kinda like me. As JimShaw said you really will want to try them on if at all possible.

I decided I wanted to buy a new bag sometime last summer, and spent until a couple of weeks ago trying on.

It's not always posisble but when it is, do it.

Now FWIW, I did end up going with a western mountaineering bag, after much trying on.... - it just fit and felt better than the others - however my purchase was a versalite - all bags are different.