You know have bricks are named x|y? How about logging where the troops are in a .shared table?
After all, script chars take up WAY less space than bricks...

My best guess is this:
shared.SirGelatina.UnitType1 = {"x|y", "23|12", "13|23"}
shared.SirGelatina.UnitType2 = {"x|y", "3|2", "23|4"}
--etc

Thats all I gots...
(I'm *VERY* sorry if I failed you!!!)

PS.Dragons can't go into catapult meshes, only catapults can; same with all the other troops.

But this is very recent, and so this might have unforeseen consequences that no one saw yet, and it will reduce the quality of the game...

As for the troops thing, i think you should use meshes, they has worked well in your other game, so i don't think in this game they will be any different... If you think this can't work (because of "meshes create lag" even though i don't completely understand it...), then you can use simple objects such as a motor part, or something, to replace some troops in the game...

Or if the lag you are worrying is the type of lag that occurs when troops move, or time ticks, and not the lag the whole game is, then you can modify the script to move part of all the troops in the game in one second, and another part in after 3 seconds, and so on...

All i can think of for now...

Oh, yes.
Without going into a wordwall of text.
I've been doing the same thing with my older computer that burnedout. Since RAC 3 doesn't have many maps that have "materials", it's pretty much usless for RAC 3, the only thing that would have to be changed is 'Plastic Quality' and it has a few side effects to it good and bad. and we all know that someone is almost likely, going to mess up something on thier Machine. 'FrameManger'should be turned off.
ALSO, there is also something called 'MinCullDistance', which acts with FrameManger. Default, it's set at 50. It culls the non-Important bricks, OR in a short way of putting it, controls how far you can see bricks in the distance. Frame Manger MUST be turned off though.

Last one was a joke

I've looked into fixing lag and viruses before, and with gui's two forms of lag emerged:

Personal Lag- lags one person, gui exclusive, and doesn't affect game ticks. WCS: One player is losses connection

Normal Lag- Lags the game itself, and as such everyone else. WCS: Game freezes, and multiple players will lose connection based on their connection strength.

Granted both will appear as just lag, but guis won't cause the usual lag as much.