2% max recommended unless otherwise noted. 1% max recommended for soccer.
I think this is a decent intro for people looking to jump into using Kalshi or Polymarket. Lays out the basic concepts, pros, and cons, better than I've heard most people explain it.
@RobertBarnes has referenced Unabated (run by pro bettor Captain Jack) in previous Q&A livesteams. I find some of their videos educational and easy to understand. I have not bought any of their services but their odds screen would be on my short list of ones to try. Especially if they're listing prediction markets too.