Speaking as a previous FAIP (well... once a FAIP, always a FAIP), prior civilian hours didn't necessarily equate to better performance at IFS or UPT. It was more attitude and work ethic than anything. That being said, if you're worried about your PCSM score, get the book that preps you for the written test and practice. Also, if you have a Civil Air Patrol near by, check them out. You can get quite a bit of your training at very little cost there. Just don't fall into the trap of thinking that CAP is an actual military organization. As far as when to take ground school, if your school allows you to take a concurrent course, I'd do it that way.
Bottom Line:
Quantity - If you want hours to pad your PCSM, use your own strategy. It will help your hands I suppose but from what I've seen, if you've got the heart, I can teach the hands.
Quality - Get as many hours as you can with the appropriate ground schooling. Answering questions on the ground costs 1/4 of the price of answering them in the air.