ECF is acting up so I can't quote the above message, but thanks for the link, I hadn't seen that thread. That looks like a very interesting method!
The PG took a week to develop its full nature in my case. When it was done "evolving" it was a harsher more tobacco'y flavor like when CB is smoked. This is not from the coil burning residue, though I know what you mean. But the PG came out honey colored and it takes a couple tanks of the mix to gunk a coil. The VG is actually the one with more sugars, etc, that is black and gunks the dripper coil pretty fast. (Not that the PG doesn't also have sugars in it.) But the 'smoked taste' is just how the PG one came out, and I feel (could be totally wrong) it's because the PG cook was hotter and 'more acrid'. When it was cooking it had a really nasty smell that could almost choke you if you inhaled the fumes. And that bitterness had to steep out of it when done. The VG cook, however, make the whole house smell WONDERFUL like CG smells.
I realize you probably want the smoked taste in your case and not the smell of the tobacco. I never did another PG extraction so can't say if it was dumb luck or what.