Stop worrying about the ideal setup for now, and get to a match. Like you said, the season is almost over. Get one under your belt so you know what it's about and worry about your gear in the offseason when you have a better idea of what you need.
^^^This...Virtually everyone I know competed in their first match with less than ideal equipment...in my case, an old Mossberg 500 pump, a dump pouch of shells and an SKS with detachable duckbill mags. Your current gear puts you miles ahead of that.
Get out and try it...if you enjoy yourself, upgrade to your hearts content (if you are like me, that'll be a journey in and of itself)...If you find 3 Gun is not your thing after trying it out, then you didn't just dump a pile of money on gear you don't need.
But I think you will love it...




















































