Polyester resin does not require any roughing to establish a good bond as the laminating resin remains a bit tacky to "grab" onto the hotcoat resin.
Before hotcoating do I need to rough up the board, and please define "Rough up"? How deep do I need to sand it, etc.
With Epoxy, If you wait more than 48 hours to hotcoat the board it's a good idea to rough up the board for a mechanical bond between the hotcoat and lamination... Just hit the lamination with 80 grit on a medium sanding pad and blow / wipe the dust off.. you can also wipe down with Denatured Alcohol and drag the sticky side of masking tape all over the board to pick up dust and eliminate pinholes and fisheyes in the hotcoat.