You want a DC rated double breaker sized to not nuisance trip from your PV output. These are utilized for switching not fusing, so larger capacity is fine.
Your SCC gets it's own fuse or breaker to the battery or bus, 1.25 to 1.5 times the controller output, so something rated 50-60A to protect your wiring. I used a switching breaker which doubles as a SCC cutoff. Get a Bussman or TTokas and not one of the no-name amazon ones - they are known to either fail or create a lot of resistance.
Good vid on the subject...
Which system setup did you end up going with? 12 or 24V?
AC on batteries?