Chaosgabe: No, you don't actually know they're doing the queued orders which is kind of weird. So you have to click them and remember for the most part. It does work for move orders though. As far as I'm aware, it works for everything. So you can chain a bunch of "move behind you" commands to get your tanks to reverse instead of turning around. And yeah, they regroup.
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Goron: Hrm... I don't know if I would personally classify the FAMAS troops as "cheap" infantry (since Motorstrelcki cost only 10... but FAMAS costs something like 30) but I will affirm that they are extremely good. Almost spec ops level of damage dealing. You're just not going to be spamming them out at the same level.
I personally use just the Chasseurs (cost 20 with VAB) with regular rifles because my role for them is to smash into tank lines and use their RPGs to nuke them at close range. I tossed out the rifles for that role. For forest clearing I use a combination of infantry recon (either Rep 2e or SAS) and a Zippo behind them. The Rep 2e have AT grenades which is excellent at nuking tanks in the forest whereas the SAS have flashbangs which instantly rout anything, including tanks. They can't kill tanks though.
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To deal with infantry rushes, I recommend you not respond with infantry yourself. Countering spam with spam is generally inefficient tactically as the enemy already has an advantage in that front as he was preparing for it the whole time. What I recommend you do is send the cost 15 tanks to the front line in groups of 4 or 8 with the flame tanks to the rear. The hyper cheap tanks are normally useless at everything except providing strong enfilade fire, which is what you need against the fast moving APCs that infantry come in. And when you lose them, it's not a particularly big deal. You should also reverse your tanks when you see APCs coming towards you and don't stop reversing until they're all dead. Anything with autocannons will also rip them to shreds, so look into the Luchs, Rardens, more AA, etc.