Actually Flyby, I expect that is a step too far for the current (old) IL2 engine which struggles with some of the latest (unofficial) additions.
I would love to have multiple layers of solid cloud so that it would be possible to fly into an overcast, come out above it and have a complete solid cloud layer underneath.
The only way I can see this happening (at the moment) would be to replace the land terrain with a cloud terrain, then have air-starts only, and then you could have a a 'Blind' layer of cloud to fly up and through, which would give the appearance of two layers of cloud that you are flying between. The problem then being, if you get shot down you would explode on the ground 'cloud' layer
Multiple cloud layers are something I hope to see in SoW though for sure!
Cheers, MP