It's not quite what I planned, and it's not quite what Steve suggested, but this is what I've come up with for the Dvina defense for this impulse.
The main reason I had to change things around is that the MECH couldn't move to the forest hex Steve suggested (where the 2nd Siberian and 39th INF are stacked with the FTR). Also, in order to move a few of these units without getting them disorganized, I had to put Yeremenko in that clear hex at the crossroads. This defense still makes the Dvina difficult to cross in the east, and protects against a Blitz-Brekathrough that could threaten Yeremenko. I suppose I could add either the 2nd Siberian or the 39th INF to the 2nd INF, but it's a clear hex with more than 2 hexsides to use for attacks (depending on the weather). Unless the die roll produces Fair weather in the Arctic (10% chance of that), Ground Strikes against either Yeremenko or the 2nd MECH are unlikely. Even if the attempt is made, everyone here has FTR coverage.
I think that this setup should limit Germany to a maximum of 3 attacks, if they are willing to risk low odds: Riga, the CAV, and the 2nd INF. That's only possible if it snows or the weather is Fine. More likely, Germany will be limited to 1 good attack on the CAV and
maybe a solid attack on one of the other 2 units, probably Riga.
The reason that preventing a Breakthrough on the 2nd INF is so important, is that HQ-A Rommel will almost certainly use his reorgnization abilities after the next impulse. That means the 3 units between Minsk and Vilna are likely to be active again if Germany gets another impulse after that. This means most of the units need to be on the rail lines and unable to be ZOCed in such a way that they can't retreat to a better defensive position . . . mybe I should add the 2nd Siberian to the 2nd INF hex, after all.
Anyway, take a look at these 4 posts, let me know what you think, and I'll adjust things in the morning if I've set myself up for a huge mistake. Enjoy!
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Edit: Forgot to mention . . . I'll be using my 3 Air Missions to get the LND near Vitebsk into a safer location, and to finally get the 2 short ranged LND into the Baku/Persia theatre. At the moment, they are both sitting around between Stavrapol and Tiflis . . . completely useless there.

Always listen to experts. They'll tell you what can't be done and why. Then do it!
-Lazarus Long, RAH