2 RE, 3 rifle, with your tech being dependent on enemy commander, tech, and army comp. anymore than 3 rifle will kill your MP, unless you kill enemy squads and are way ahead.
From a 2v2 perspective I've been having success from.
3 rifles
bar/bazooka upgrade (1 of each for each rifle)
Captain
Ambulance (before or after Pack dependent on how the health of squads are)
Pack Howitzer Follows behind the infantry advances to allow normal fire and pull it back when theres a chance I may be forced into a retreat
2 - 3 AT Guns
Stuart if its OKW with a walking stuka or head Major
I will use Airbourne for droppable MG and Airstrikes
or
I will pick Infantry and replace the BAR with a .30cal and then get priests
I've found that the US AT gun, 2 in depth, are more reliable than trying to get tanks out quick and once you hit Vet 1 for the increased sight and range.