Norwich -
Welcome to your newest addiction....
Couple of things to look over before you head out - every new shooter for IDPA should have a look at the best info on IDPA shooting for new folks -
http://nepaidpascores.net/misc/Welco...A_Shooting.pdf
The North East PA IDPA Scoring website (
www.nepaidpascores.net) is the place to find IDPA matches in central and eastern Pennsylvania.
Your cover garment should be able to cover the holster with your arms extended in a "T" or "scarecrow" position. You can also cover up with nothing more than a T-shirt, but that really slows the draw down. A regular button shirt, vest or light jacket will work. Whatever you use, just make sure it's clear of the holster when you go to reholster.
As a SO, the hardest thing to get shooters (new or old) to do is slow down while holstering - most think it's some kind of race. Just be patient to the SO's commands to "unload and show clear - slide forward - hammer down - holster".
Enjoy it, and be safe - it's a blast!