Hi deisel, be careful creating a texture in a mould. It can cause the resin to lock in to the mould. On release you'd either leave bits of resin behind or possibly damage the mould.

I work with composites and a shiney mould is what you're looking to acheive for best release to maintain the mould lifetime. Refinishing the mould after a lock-in would of course make the mould slightly larger.

As for finishing the mould I use wet and dry paper through the grades to about 2000 grit. Then machine polish with mops for a mirror finish. You can then use a scotch pad to take away the shine from the moulded part. Depends on what kind of texture you're looking for i suppose.