That Plumcake sounds delish! Might have to add that one to an order soon.
Your thoughts on filtering are just fine. I would suggest after you filter, winterize (freeze) this NET for a few days to allow the gook in the tobacco to precipitate to the bottom of the jar; then filter again, but be careful to leave all the gook at the bottom of the jar.
Then, evaporate the PGA NET down to 1/4 of the original amount; open air, in a closed cupboard… 24/36 hours should do it. However, keep an eagle eye on the evap process… you don’t want to go past the point of 3/4 evap.
Now, you can leave the final amount as a flavoring (suggested) or process/blend it with whatever base you wish.
Hope that helps!