Hunsta have a read of my fin primer on this site may help, but briefly try the centre fin in different positions, when you find the spot that suits your surfing mark the box with a waterproof marker or pencil so you can put it in the same place again.
If you have some cash or can scrounge or borrow for a while experiment with different centre fins, your questions are not totally nooby , most long time surfers have a set of ideas on how fins etc work for them usually gained by having the experience.
ADVICE TO ALL LEARNERS HERE you get the skills and experience by having the experience as often as possible and refining everything as you go.
Just re read your post, try side bite in with different centre fin positions too three time the learning there, if you are no trouble catching wave then it is about noticing the differences you are going to get.

I've taken up troll hunting just for fun, instead of a rifle I'll just use a pun!