Fixing Audio Spill Between 2 Mics?

i plan to try out this invert as discribered in second part of attached video. But i do know yet hot it will work

https://youtu.be/yuVwHp4iYKw

I can only think of one easy (well relatively easy...) way to do this automatically. You'd need to use the signal from one of your tracks to 'duck' the other track so that it was a lot quieter whilst the first mic was active. And you'd have to do the same thing the other way around (start with the raw track, not the processed one). The only real snag with this is what happens if both contributors speak at the same time, but since you'd be creating an automation track, you could modify those bits by hand afterwards, the problem being of course that they'd duck each other!

I'll be the first to admit that I haven't tried this (I always fix these things at source, or don't bother to correct them, as generally they sound fine), but I'd be intrigued to know whether it's workable or not, as a lot of people seem to run into this issue. I might set up an experiment later to see what happens...