Wish all I had to do was develop vent system's for shop N benches.... doh.
Google images of Filter 1,Benchtron "backdraft" sanding/grinding/finishing ,stations.
Basically,you have 3 choices.... up,down,and back,draft systems.First is the "plumbing"(duct arrangements)....second is,type and balls of the fan,third is what... if any,filtration(can be a total loss system,not requiring recuirculated air).
My last system was a total loss,utilizing an eBay procured 6" ,inline "duct fan".Ancient Lyman pot was housed in a custom enclosure with a custom rolled "hoody" venting outside.It was up draft.... and worked the treat.
If I wuz building from scratch,no holds barred,would go back draft,recuirculated, on a reloading bench with an auto,solenoid to vent to outside when casting.All sounds WAY more complicated than the build BTW.
ALL good,best of luck with your project. BWS