You can put ducting. But the total diameter has to equal the output diameter. I think for your shop, what you ended up doing will be fine. Think about getting some of that bubble wrap insulation or foam on your ceiling.
I'd squeeze that sucker tight to the building and make that square hole fit. i swear as soon as ppl quit asking me to fix their junk I'm getting back on My projects. lol. It's definitley going to be cooler in your shop now, It sucks when you can't see because of the sweat in your eyes. 🤣
