I got Cathe's red tubing and I love it! I can lift 5 to 8 pounds like for biceps and shoulders. If that can give you a range how someone like me has strength. If you need to put your foot on the band and then stretch it over head, this was perfect for me. It was stretchy and I still felt challenged. If you find some of the exercises for the tube is to easy you can always double it.
As for the fire Walker band I bought the variety, 4. I found that the pink band is a little bit longer (easy) then the others. But, like an inch more, nothing too crazy. But, if I were you I would buy the variety pack because you may need a harder firewalker band on some exercises and then on others you might need more length.
Hopes this help! By the way I don't make any money with this review! Just wanted to help those buying these. They are still great!!
Hope this helps,
Jennifer Denny