How Rough Should the finish on a Pizza Peel Be?
Based on personal experience:
The critical issue is that the peel be textured enough to &quot;hold on&quot; to flour or semolina, allowing the pizza to slide off of it.  This means the ideal texture is the same as a new cutting board, oiled wood sanded to 120 grit or so.  It's not rough as such, but rather just not smooth like plastic.  I once got a bamboo pizza peel that was high-polished, and I found that 15 minutes with some steel wool was enough to make it usable.
The other issue you're going to have it that shellac is probably going to melt or catch fire in the pizza oven.  So, while a light sanding with 100grit paper or even steel wool would probably do it for &quot;roughing up&quot; the pizza peel, you might find you have to strip off all the shellac to actually use it.