First time cooking Ribs. St. Louis Style, membrane questions + more This is my first time cooking ribs so I feel I am making some rookie mistakes.

I forgot to peel the membrane off of the rack of ribs I plan on cooking later today and they have already been soaking in the marinade overnight.

My questions are: Will the marinade penetrate the membrane and still flavor the meat? If I peel the membrane off after I pull the ribs out of the marinade, would it be worse than if I left the membrane on? 

Cursory question, How often should I baste my sauce on the ribs? I have seen reports that it should be anywhere from once or twice towards the end of cooking, to every 10-20 minutes through the whole 2-6 hour process depending on temperature.
The membrane will inhibit flavor penetration but not stop it completely. If you have the chance you could pull the ribs out of the marinade, peel them, then put them back and they'll get a bit more flavor. Otherwise peel before you cook them, you won't make anything worse by doing so. 

As for the basting, there's a lot of opinion on this topic. Personally I've tried more basting and less basting and I've never found benefit in basting more than an hour from the end of cooking. The ribs have a lot of juice in them, basting them isn't going to keep them any more moist, what you are trying to do is impart flavor by building up a coat of the marinade/sauce on the outside. I've found that basting every 10-15 minutes in the last hour seems to give as good result as basting longer, and it's less work.