This is pretty expensive to always have 2 squads together (2x280mp=560mp). You should counter the fact that he wasted 2 of his upgrade slots on zooks and send two lmg grens against it. They should win if positioned properly and cost less to buy and reinforce (480mp) meaning you win on every engagement. Cheaper price also mean you can sometimes pump 3 grens against him. Eventually it will come down to better micro and positioning.
I wouldn't suggest using mgs against usf on certain level when people know how to smoke. Instead you can buy a sniper, it bleeds usf really hard.
If you feel that you still need an mg you should always use it in a group of two (yeah it's expensive, so its not often a good idea but its much, much better than lone mg). You position them in such way that one is facing opponent and the other is behind covering one flank and the point where the 1st mg is set up. When the 1st one gets smoked you reposition it behind the 2nd one, when opponent comes out of his own smoke he walks right into the second mg. At least one squad is suppressed at this point, the others can smoke more but then you just keep repositioning your mgs behind. The "tentacle blob" of smoking riflmen cant go past that if you do it correctly. Remember to always place your mgs in green cover, or in worst case in yellow one.
Oke I will try this. The problem with the grenediers is that they have 4 soldiers and he had m10s. Those tanks can run over my soldiers and destroy the entire squad. He basically had one m10 per assault group, it was a very smart idea of him.