Charlie Company is a great rule set. I played a couple campaigns with friends years back and was so impressed, I bought a ton of minis and the rules. It's meant for 20mm (1/72), so your Platoon20 figs will be perfect.
I's a tabletop minis wargame/
RPG. Each player plays an NCO, represented by an actual miniature on the table. That guy with the AR-15? He is YOU. You've just started your 1 year tour and need to survive twelve missions (abstract time for months) and get home. You have a "Game Master" that designs each mission and plays the NVA and
VC troops, which are hidden on the board. You aren't allowed to speak to each other unless you have radios, send runners, or you're standing next to each other. There's a 'radio' phase where you're allowed, like, 1 minute to discuss plans, assuming you have a radio.
The game scales nicely from a skirmish to an actual battle. My first campaign, there were 4 of us playing as Squad Leaders, each with 9 other men. The 2nd campaign, though, that was the best. There were 6 of us and we all played members of one squad. That was so badass... 'till I stepped on a mine...
We used the other 4 squad members as runners, etc. Some missions, we were ambushed in the jungle and had to fight our way through. One mission, we just went to a small village to search for
VC caches of weapons and rice. Never saw a single enemy. Just trekked through some super tense turns in the jungle, expecting an ambush, then confiscated weapons and rice.
One of the most notable moments was when we radioed for dust off for a couple guys wounded pretty badly. When giving our location, our radio guy said something like, "Look for the yellow smoke" as he popped a canister to alert the helis. Next thing you know, we started seeing 2, then 3, then 4 columns of yellow smoke rising up from different areas of the table. Our dust off heli went to the wrong column and was shot down by NVA. Our
GM was a tricky bastard and, since our radio guy just said it plain as hell over an open channel, the NVA heard it, too, and acted accordingly.
So much fun, that game.
It's only $12 on RAFM's website.
Ghidorah