I do basically the same build except I get one or two rear echelons first. Rushing an M20 almost always makes sense.
Oh? I take it one of your RE goes for fighting position at a fuel or muni point?
Against which faction?
vs Wehrmacht I usually go 3 riflemen -> lt -> M20 -> ambulance -> bazooka -> airborne with browning lmg -> major -> M8A1 -> Sherman -> Bars. If needed I paradrop AT guns.
Grenades are an option but usually those I play vs can dodge them, so at max I rely on the cooked grenade of airborne troops. Pathfinders are another good option but I usually prefer getting them vs OKW.
vs OKW I usually go 3 riflemen -> lt -> M20 -> Pathfinders -> ambulance (I usually get a 2nd pathfinder at some point in the game, they work well in pairs)
Then if my M20 dies to an enemy vehicle and I really need to invest into countering that else I wouldn't be able to reach medium tanks in time: Captain -> Stuart -> AT gun -> Major
If instead I can keep the M20 alive long enough to have a good map control during midgame I get Major directly and rush M8A1, followed by a Sherman and eventually bazookas or bars depending on what's the most pressing problem my infantry is facing.
Besides the matchup I usually try to not spend all my munitions, especially if the game is a close one, to save for the P47 attack 
I mainly go against OKW, since there seem to be a ridiculous number of OKW players... How do you use pathfinders actually? I know about the long range part and behind rifles but still doesn't work well for me. Something wrong I guess?
Another question. How do you play USF late game properly? I tend to dominate early game but lose late game eventually. I get a few shermans but I find that if I spend resources on E8s then it's much better but still have a weak late game.