221 OKW opening vs Def Tactics

Tried same opening with extra engineer since it seemed to work decently.
Got some quick capping with engineer and saw he tried to rush my gas with his kubel but my engineer gave him pause which gave me a chance to chase with clown car. About 10 secs later I saw a 221 which threw me off, never saw someone rush that unit however I was able to push him back without losing to much. I pretty much controlled both gas due to his lack of units for a bit. I built some mines and bunkers on right side of map to slow down his recapping.
At this point, game boils down to me catching his tanks(P4 then JP4 then P4) out of position and rushing them with AT overwatch. GG

Some thoughts so far on Commander:
I dont know when or where to use AT gun, seems weak and useless. Rather use PTRS and save MP.
2 engineer opening is weak but does allow quick capping so it feels my go to for this commander.
MG with penal is strong, helps since there is no elite infantry.
Sometimes I feel I need a 4th Penal to push a little better. Mortar with sight does help with this a bit since it softens them up before the fighting really starts. Once it hits VET2, it softens them up a lot. A LOT.