So here's the settings I am using:

I sort of worked that out by trial and error starting with 'hard' but adjusting the Soviet values to 100 (prefer to play without malus so as to gain a feel).
Now here's the situation, turn 14 on the Northern and North West Fronts:

The key is the AI, which has been casual about its flanks all game, has abandoned the Volkhov line completely (I've done some recon flights and there is nothing there) in order to prioritise that breakthrough in the southern sector (its done much the same in the Ukraine, but a bit less dramatic).
In more detail, this is the Volkhov:

and this is its breakthrough

Now the reality of course is I can seriously isolate all that lot in a turn, not just with a one hex screen that will be quickly bounced out of the way but to the point where their entire AGN is doomed.
I don't want a short game so happy enough to roll things back a turn or two. I noticed in my last test, the AI does seem to overdo narrow deep penetrations - which is good, up to a point - so its not just the settings I've picked. But this is more radical, so the main question is how can I adjust back the settings so I feel seriously threatened but the AI is saved from its own aggressive tendencies?
Turn before, it had a decent screen along the Volkhov and the breakthrough was running into the treacle of a mass of 1CV formations.