Rick
I've heard good things about Games Workshop's acrylic spray lacquer, which I think comes in Matt and Gloss - although the Matt is quite glossy. On the basis of my experience you should avoid Polykote, as it yellows very quickly. It's also incredibly sticky and will foul up the floor of your workshop for days while it dries!
Personally I use a cheapo Badger 250 "airbrush" to apply Humbrol Clear Cote Satin. An airbrush needn't be expensive or elaborate for such simple jobs, and it opens up your choice of paints enormously. A compressor seems expensive but, by the time you've bought a few rattle cans or those exorbitant cans of fresh air, you'll have spent as much and have nowt left to show for it except empty cans!
Works for me.
FLJ