OKW
Intended: T1 or T2>T3
From a 1v1 (and ~2v2) perspective I've the impression that the OKW intended build is T1 > T2 or T3. First because T1 ISG and IR Halftrack does not require fuel and also because T2 into T3 is so fuel consuming. If you get just one FlakHT, one puma and one stuka out from T2 it's already 215 fuel. Unless you're sitting on 2 fuel points / don't need T1 to secure 1 fuel point (in which case you're probably winning already) it seems you won't get anything out of T3 before a long time..
If you were not going to get units out of T2 to use fuel for T3 then why not get T1 in the first place?
I'm even more convinced of this with the upcoming decrease cost of Ie.IG 18 ISG and previous decrease on the IR halftrack. Decreased reinforced cost for Sturmpios will let you get more than 1 squad (2 maybe 3 total) so can skip T2 and still repair efficiently. Relic seems to promote for more use of T1.