ok... had a few minutes this morning....
literally just a few minutes.
if'n you're going to make a pan, you really would be a bit ahead by smoothing out the form (in this case the aluminum tape) the best you can. i didn't spend much time doing that, it's good enough for my purposes.
a release agent of some time will seriously help a lot, even if the form is a throw-away like this one. car wax can work well, but some of the stuff can react with the resin. a good carnuba wax should be fine. i use a spray on release agent; works a treat, it's actually made for this & i've got a lot of it. (i made fiberglass & carbon fiber parts for a few years)
i pre-cut the fiberglass mat to the shapes i wanted... then start laying and brushing/tamping the resin. i mixed it pretty hot (bit more catylist than they say) so i could knock it out fast.
4 layers of glass on most of it, 6 in some areas.
once it cures, i'll pull it off, smooth it out and trim.