Can't do much as Merika' vs dbl Kubel until the Lt. comes out at around the 5-6 min mark. Then you can get an MG or Mobile car or AAHT. Comes down to trying to avoid the obvious Kubel positions and either A. camping in buildings, or B. hiding behind them and attempting to flank the Kubels.
-If there are no buildings > you are doomed
-If opponent uses truck push and makes no mistakes with Kubel >

-You go for LT > he goes for AA HT + Puma
At the moment i don't see how you can come ahead on this engagement:
2Rifles or Rifle+AE
RE
vs
Pushing/Breaking building truck
SP
Volk
Kubel