Re: 1st big project, bronze thru-hull
if you can get some chopped strand mat and make 3 or 4 little circles to fill the hole you're patching, that would be better. Wet them out thoroughly and stack them neatly in the hole. The foregoing sounds easier than it is.
I've not read Mainesail's article, but I have found that the shrink wrap plastic that is filling boatyard dumpsters everywhere this time of year makes a great backing material for filling a hole. It's got some body to it, and epoxy will not stick. Put a sheet against the hull, back that further with a piece of plywood, and jam it all in place with a stick and a wedge.
Edit to add: Holy heck that's a manly pile of bronze.
Bashing about on Lake Ontario and Beyond
"Ariel" '79 Endeavour 32