Having encountered 36k B-17s bombing
radars recently (I didn't even know B-17s were perked!

), it seems to me that avoiding the fight is what some bomber "score enthusiasts" are all about. Not asking them to hold still and die, but 36k? Come on.
How about a 5mph wind layer at 30k and above?
The wind would slowly change direction like a clock, say a full revolution every two hours to keep things fair.
Planes could still fly at absurd heights if they wanted to be Nancy-boys, but it would be harder to bomb with impunity from up there.