For me, the cubit puts me too far forward. I have long torso and "ape arms" with short inseam. Everybody is different. I would make sure your seat and legs are correct, then adjust stem and bars to tweak the fit. The bike geometry and top tube length has to already be within an acceptable range for your physique or it's pretty tough to tweak it. Plus you need to dismount without injury. Sure, you could probably ride most anything with enough compromises and great care. I wouldn't, though. I think you are wise to stand firm on frame size first, then make minor adjustments for fit. I would expect my LBS to make these adjustments to a frame size I like so I can ride it that way before deciding to buy it.

God bless!

-Ron