It helps to know what tension you are using, at least round about, so that you can plan out a cycle of attack..which will yield much better results for most than just random guess work plus keep them from overdoing it at first. Especially since if you were planning a dynamic cylce for intance it would be easy to use too much resistance at first where the accentuated eccentrics could really get you inapacitated putting a damper on your plans for a bit. A guy who benches 200 probably shouldn't be getting 60 or 70 pounds of tension at the top, for instance. At least until you get to know the bands and how you do with them. Given that, I'm only talking guidelines because there are many many ways any one individual can incorporate them.
Heck one of my favorite things is to use heavy bands around the back and hands with a light bar.
Accomodating Resistance