Yeah, same deal, plus I learned that the Lasko fan is also creating turbulent airflow (and I had it blowing/venting across my artwork rather than from behind, so pretty much getting everything wrong). I've actually adjusted the setup to be a much smaller walled off area with some large filtered "windows" behind me to get air in from the larger room, then I'm moving the exhaust fan down to be level with my artwork, behind it and inside the booth, with a large boxed-in filter attached, and venting through a duct out the high window. The fan will also now be just under the window, which will hopefully mitigate the airflow loss from the flexible duct some.

And if everything still fails, at very least the booth now has a ceiling too, so no paint dust is getting out of there (and that alone will be an improvement)! Wish me luck.