But pound for pound do you get more hits from the IL-2 vs the IL-4 or Pe-2? If the IL-2 is more accurate, then aren't you better off with a higher ratio of Tactical to Level. Also, does it matter what types of aircraft you base in the different types of bases?
I've been toying with planes a lot in my current game against German AI (custom settings around 120/90). In this beta version, bombing runs on airfields are more effective which makes level bombers worth using for that purpose. Of course, that is in part because the AI can't handle air base positioning like a human player would, so I can't tell if this is actually viable in a pvp game. That being said, I think the soviets can win the air war against axis if they do something around those lines :
In the opening turns, do the usual air groups shuffling between bases and national reserve; try to prevent losses on the ground by keeping empty staging bases in every air command.
Assign your level bombers and your best modern fighter groups to long range air command. This is necessary because modern fighters have longer effective range and will be needed to face the axis fighters when they show up for interception.
Monitor your air groups closely; I found I would rather manually assign good planes to experienced IAP groups (at least 50 to 60 XP) than waiting for newly formed groups to get gud in the national reserve, wrecking precious airframes as they do so.
Use obselete fighters, especially I-16s, for PVO-style interception. They are mostly going to get wrecked, but those who don't will face increasingly poorly defended axis bombers. Crappy equipped groups can be given good planes after they had a field day shooting unescorted bombers.
Consider training new or bad long-range fighter groups by using them as escort when bombing the Fins, as they have fewer bases and less fighters to protect them.
New air groups should be mostly IAPs and ShAPs with the occasionnal recon and transport as needed. You should have enough BAPs already to drain off their airframe pools should you run into trouble a few times. Don't forget that destroying the Luftwaffe mostly allow Il-2s to grind down the Wehrmarcht more effectivly, preventing ground losses for you at the same time.
Speaking of which, getting the most of your ShAPs evey turn is key to wear down axis forces. When they are not shot down, even crappy i-15s and RZs can take out many hardly replaceable axis guns.
In my last game, manually managing tactical bombing has allow the VVS to claim around 50% of total axis gun losses in 1941. I think this potential is somewhat unappreciated by many players.
Keep only 1 our 2 bases for partisan resupply and assign them your precious Li-2s which should be rotated every turn to prevent excessive losses by fatigue. Make sure these bases have near max TOE and don't assign anything else to them (no recon). Imo, Il-4 and Pe-2 are not very effective in that role and should be keep on day flying, espcially since they perform rather well this beta. Finally i noticed that for some reason the same VVS base was doing all the resupply flights in my last game, and was using only one of the many available transport groups to do. I don't know what was up with that.