I am not an expert, but recently hit rank 650 USF.
Keep in mind Sturms are expensive + take extremely long to build compared to volks.
If you're in green cover and they charge in the open against your rifles, you'll win the fight most of the time, if 1v1. And if it doesn't, take a 2nd rifle squad to assist. But from what I've experienced, rifles win against charging sturms when in green cover.
2rifles -> 2 sturms imo aswell. Just play smart and focus 1 squad down first rather than both at the same time + use buildings.
The moment he has his kubel out, you'll indeed have to wait for stuart/capt or m20. But if his kubel stays with his sturms, you can capp the other sides of the map, he'll have no map control whatsoever, abuse it.
So in a nutshell, don't fight sturm+kubel combo in the early game, just avoid it. It won't take long till you have capt/m20
And I personally don't recommend fighting a kubel in a 1v1, as you'll bleed while he doesn't.
