Spam grens, skip T2, get a stugIII, kill T-70. It costs a soviet player more fuel to get molotovs, T1 or 2, T3 and a T70 than it takes you to get a stugIII if you skip T2
Correct me if i'm wrong:
Stug 3 + Tier 1 and 3 buildings + teching cost:
170 fuel
+10 Tier 1 building
+25 Battle phase 1
+35 Battle phase 2
+25 Tier 3 building
+95 Stug 3
-20 starting fuel
T70 + Molotov + Tier 1 and 3 buildings:
160 fuel
+25 Molotov
+40 Tier 1 building
+90 Tier 3 building
+55 T70
-50 starting fuel
These numbers only work under the assumption of equal map control. 5 Conscripts with molotovs WILL hold more map than anything the ostheer T1 can provide. The Stug comes several minutes to late, in which you most likely will lose total map control. Plus, the Soviets have more manpower to spend until both units hit the field.
Even a fuel cache won't make a difference, because +3 fuel equals one normal territory point (which you most certainly won't posses at that point).
-Correction: The Support Armor Korps costs 25 fuel.