sounds like besides a Valve Cover Gasket Oil leak you have some blow-by issues.
You might consider replacing the Valve Stem Seals and/or soaking your Pistons/Rings with Marvel Mystery Oil.
Compression Test...how low is low.....
A few people have put something between the Air Filter and where the Breather Tubing comes out to act as a trap for the Oil before it gets into the Air Filter Housing.
I believe it was ForcedInduction that said he used a Air/Oil separator that is used on Air Compressors.
Now, that I am thinking about that is it possible that your the Blow-by breather is plugged up inside and will not let the Oil go back into the Crank Case?
Mine has a Turbo so the intake system is different but below is what I did.
Washable Air Filter and Intake Mod , With Larger Breather
Washable Air Filter and Intake Mod , With Larger Breather
It might be possible to attach a different Air Filter to the inlet of your Air Filter Housing and there by keep the Air Filter Element from getting saturated with Oil from the Blow-by vapor.