Rule of thumb I use of for Gunboats: Make sure the 'Maint Capacity' is at least equal to the amount of parts needed to repair the engine, once. Very annoying to have the drive suffer a maintenance failure and not be able to repair it, leaves gunboats littering space while you scramble a tender to pick them up.
I also have the same attitude about gunboats that I do about fighters, don't bother armoring them, if they take hits they will die. I have had some gunboats survive fleet combat, but its pretty rare. Either they never get targeted or they go *boom*. In the case of the Moccasin, since you have the spare room, and a decent speed/throw weight, no reason not to have the armor.
Tossing in a tanker gunboat helps when running gunboat squadrons around on their own. I haven't used a point defense gunboat enough to decide if its worth it, but I've had fights where I ended up splitting off point defense destroyers to escort gunboats on attack runs when I didn't have them.
My current gunboat squadrons run about 20 attack boats, 2 'command' boats (ASS, decent thermal sensor, additional fuel, probe launcher), 2 or 4 tankers (strip the launchers and MFC, stuff in fuel). I make a tender for fleet operations, the same size as the fleet destroyer (which is normally 6000 tons), at least the same speed as the fleet, give it a jump drive, enough hanger space to dock one gunboat, and fill the rest with missile reloads, spare parts and fuel. This lets me send a gunboat squadron + tender off to do commerce raiding.