Some matches around here have 20+ people but aren't sanctioned, I think others are ARA. I just need to get shooting at this point and attend some matches when the virus blows over. I've been emailing some local match directors. They're all single gun events, no spotter rifle required. It's honestly a bit confusing with all the different sanctioning bodies, sanctioned versus non sanctioned matches, different targets, some allow 1 piece rests and some don't, different rifle requirements.
Ah, now we have more information. You are doing just fine and your questions are posted with a very healthy attitude towards getting good advise. I have seen your rest posts and defiantly get a two piece rest. My rookie year in ARA placed me 3rd in Iowa, not a particular hot spot of RFBR shooting but there are a couple of very good shooters there, using a 2 piece rest. A two piece will serve more opportunities to shoot than a one piece, simply because of different rules in different situations.
As you get more experience, the differences in sanctioned, non-sanctioned, and club rules will get easier. Don't worry about the confusion, it will get better, promise! Also, initial cost of getting started can be daunting. I had my original rest set up and flags before I started shooting sanctioned, or organised, RFBR matches. My big cost was buying a new rifle built by a competitive smith.
Test ammo, to the best of your budget, and start shooting matches when the pandemic allows. Keep asking questions in the same demeanor you do now. A lot of guys with experience are turned off by people who ask questions and then want to argue about answers. I see none of that with you. From what you have now explained is your objective, I think you are starting with a sound equipment base and hopefully you will stick with it and learn more from getting match experience and rubbing elbows, when elbow rubbing is appropriate again, with other shooters at matches.
Welcome to the rabbit hole! Just remember, no one gets paid anything to shoot RFBR, it's a game for fun and personal challenge. Also, you control how deep you want to go down that hole!