I used to ride flows right after they first came on the market. I rode them for 5+ years. Converted every friend I rode with to flows. Great binding really comfortable.
Then the cap straps came out and I tried them. I moved onto Flux and many others. Flux were good bindings. I'm now on the k2 auto evers and to me they are the best binding I've ever used.
MountainManCO, what type of boot do you have? I like the stiffest boots I can find. Best boot I ever had were the 32 forecast, almost as stiff as a ski boot. I tried the Burton DriverX that everyone says are really stiff and was not impressed. Currently ride the Northwave Legends, way to soft for my liking but they fit like a glove.
As for riding without a highback, I see no reason to do that unless you are some crazy freestyler. Even then, just get a softer binding. You will not be able to remove the highback from flows, that is what makes the whole binding work. Ride with a highback, you will like it so much more than just relying on the boot for support.