As for tanks, I honestly find that they're largely unnecessary. Currently, I usually opt for the crocodile or valentines
+1
Honestly the crocodile is the perfect counter to OKW so long as they don't have a panther (it can pen and take deflections from all other OKW late game vehicles except jadg, in which case just spam infantry if he gets a jadg). If they go for KT just get double at guns or a firefly (with upgraded tulips to stun if possible) + crocodile.