Which Primer Over Gelcoat?

[4xFoorOffroad]

Have a bunch of stained up panels and would like to make my carport ornament at least a little less of an eyesore. Any recommendations on primer for gelcoat after I sand the nastiness off of it? Polyester / epoxy 2k? I just don't want to have to redo anything when it's time to final paint by using the wrong kind and having to sand it all back to gelcoat.

Thanks