There was a membrane on the two I smoked. I did remove them.I haven't smoked St. Louis style ribs for quite a few years. I'm a baby back ribs guy, too. Maybe I'll have to try the St. Louis style again, sometime.
Also, I've noticed that the membrane has already been removed on the last few baby backs I've bought (last few years I have smoked only a couple times a year). I always look for it, though. Am I to assume everyone does remove the membrane or is there anyone who leaves it on?
I have an older side heat smoker and use coals for heat and wood chunks. For wood chunks, I usually use a combination of three woods in any combination...apple, cherry, pecan, peach, (any fruit wood) and hickory. If I use mesquite, I use it sparingly.