The reason you are struggling and also the reason you are not getting the answers you want is that there is no one right answer. Pick a program and stick with it. Whatever you get will be better than if there were no programs or if you didn't join one. Trying to find the absolute one best answer will drive you nuts and not accomplish anything - IMO.

The decision is not irrevocable. Most FTers have collected miles in multiple programs and changed their priorities as events in their life has changed. This is not a life-determining decision.