Moving the vent to the other side of the house alone will be huge help, since it’s so close now to the air intake for your furnace, you are drawing the exhaust back in and running through the furnace and distributing throughout your house.
I definitely think you are on to something here. 
A few weeks ago when I had let the GF run a little longer than I should have before cleaning, I could smell it throughout the house, so it was indeed going through the furnace. Not pleasant at all!
I’ve done a bit more testing with my new setup, and I think it is good enough that you can’t really smell anything more than 4ft away, which is a bit less than the distance from the GF to my furnace. I plan on cutting some leather and acrylic soon, which will be another good test. Hopefully it works out, I may end up just leaving it sit on that side. I have another window on the other side of my basement, but it is on the more finished side but I don’t want to have a bunch of duct work running. Maybe I’ll just call a professional/HVAC engineer out to see if they can run it from where I want on the workshop side. There is probably 30-40 ft that would need to be run. I like your idea of doing a jtrap also.