If the cowl is 40-60 sized and your plug is solid, there is an easier way to smooth out the resin. We do this with Quickie 500 front ends after we reinforce them to hold the cloth tight, as well as give a smooth finish. The fuselage front is 2 1/4" square
(rounded corners) and goes back 5" or so with a rear size of around 3 1/2"
(about the size of a 40 cowl). All you need is a medium to large round balloon. Once all the cloth & resin has been applied, blow up the balloon a couple of times to stretch it out some. Blow up the balloon one last time, but this time, place the end of the balloon on the front of the cowl and push the balloon down over the cowl as it deflates. This will force the balloon over the cloth and basically shrink wrap it. you can even rub out any spots that look odd thru the balloon and not get your hands dirty!
Let the resin totally cure
(24 hours or longer) and then tear the balloon off. You should have a very nice finish with minimal sanding left to do.
As I said, make sure your plug can take the pressure of the balloon, and test this a couple of times before you have the resin on the plug. It works like a charm on small parts.
Best wishes,