Good for you for experimenting and trusting your ears.
As long as nothing blows up, or now has a reason to, why not (thanks Al)? I was piqued by the Nordost write up -- to attach the leads to treble and mid from a single cable. In their case they fill the gap with their jumpers, but it seemed like they were essentially balancing the current load. Biwire, in principal, should do an even better job since it would be truly balanced.
No idea. I wouldn't have posted it if it didn't make a difference. Even Nordost doesn't know why it works. IOW, theory can kiss my axx.
Oh, and always, YMMV