Here are a couple of fans that are being used by some folks for their short run exhaust systems.
https://www.globalindustrial.com/p/h...hutter-mounted
https://www.industrialfansdirect.com/products/sf16c3
The second one is the one I'm going to use in my next studio.
Quite a few people use a vent hole with a fan mounted in it straight out the wall from their bench.
This is a picture of my work bench with the exhaust going out the back of my bench.
Also I think 30" is enough depth for your bench but you may consider making it 36" instead. I've found that between tools, glass color rods, tubes, and other supplies my bench gets pretty crowded.