Gas forge ventilation via sheet metal hood

[Adodero]

I've looked for concrete answers on this question, but mostly ran into questions on coal forges or speculative solutions, so I'm curious if someone has any input or has tried this. 

I have a fairly large 2 car garage (2 cars + room on either side for a shop, could probably fit 3 in) with several windows and a large door. I'd like to run my propane 2 burner NC forge in the garage and vent the heat/fumes outside. I understand the CO issues and have CO monitors at floor level, head level, and a gauge next to the forge, along with fans in each window and a fan blowing air into the garage from the outside via the garage door. My main concern is preventing heat and fumes from collecting on the ceiling, which is about 11ft high. 

My thought was to use a sheet metal hood with a lot of space on either side, mounted as high above the forge as possible (realistically the top of the hood will be about 4-5ft above the forge), to capture the fumes and an inline duct fan to blow the fumes out via 10-12in ducts. I figured mounting it as high as I can would allow the air to cool a bit, but I'm not opposed to lowering it. I took some inspiration from hoods used by glass blowers to vent fumes. 

I've tried to measure the temp of the fumes/air above the forge while it's running, but it's difficult outside to get an accurate measure since it moves around. 

Has anyone successfully done this or tried it? 

[Lateralus]

this might help you?

let me know when you have questions