I always try to stick to 4 engi's and cap then 3 rifles, triage. Getting wsc is always risky, sometimes a puma can pop up out of nowhere and set you back. I tend to get the m8 first then triage/wsc/at guns if you need to/bars/howi. And a howitzer I get 90% of the time. Also play versus good players will help.
I want to show how I think you need to play as Americans against standard Wehrmacht play.
Bring 3 Pios for fast map control.
3 Rifles to hold your map (do not be too aggresive).
Bring fast WSC (because atm every wehrmacht goes at least 1 Sniper).
Also try to bring fast m8.
Now just defend and disturb everywhere you can.
I do not claim to be pro and i dont know if that works against PROs.
But up to Level 10 I would say GG.