I did this quickly at the time of writing the post. [;)] With or without Pioneers, with or without the HQ, I've never failed to take Riga using this method with these two units hasty attacking from the east. One time I think it took 3 attacks but because I forgot to attach anything or more leader up and they still took Riga. It's automatic and normally happens on the first attack.
I repeated my Riga turn 1 test with 100 primary attacks. The conditions 1) 4 air ground attacks, 2) air ground support, moving air field within 8 hexes of Riga (support triggered 90% of the time), 3) Pz 1st and 6th divisions stuffed with SU's (including 2 pioneer and 1 Jgd) and 4)Corp HQ within 5 hexes of the divisions. The results ?? Average Soviet adjusted CV 146 (max 909!!) and German 460 (max 660.) Retreat/helds ??? 71% of 1st attacks, 20% of 2nd, 5% of 3rd, and 4% of 4th. There were no "failures", so to speak, but 9% of the time the Soviets would reoccupy Riga.
Interestingly, 25% of the successful attacks were at odds of less than 3.0. This implies a 200-300 attack run would more accurately reflect the true odds of success/failure.
The data is interesting for sure, but to me it's a tactical problem that is already solved. Goal - Take Riga Turn 1. Success - 100%. Failure = 0%. Soviets can only reoccupy riga if you let them. In a situation where I failed 3 times in a row, I would probably move MOT unit to occupy Riga as I don't want to have to attack it again on T2.
