I understand your qualms about system/ tradition, in my mind it's better to have faith in toughs who have gone trough the "process" and then make your mind-up on what to keep, or not. (Did that make any sense?) If you are a solitaire or work in a small group the ecstatic/shamanistic elements of feri is probably one of the easiest ways to build energy and "brake trough the vail" (psychedelic drugs being the other obvious one).
And as Morgan said about taking on different influences in feri and making it your own, is about purpose (what you want out of your "spirituality"), the same when your writing ritual, (to ty in with the first part of the entry). If there's a clear purpose that everybody is working for the loser the ritual can be constructed but paradoxically, if you construct a ritual where the participants get more freedom to "put in there own personal work" a more rigid structure is needed to make it work.