Here's a suggestion, if you want to go the route like the ventilation tutorial above.
Use a 6in to 8in duct adapter for a funnel.
A little bit of 6in bendable ducting between the funnel and solid duct so you can adjust the funnel position.
Some 6in solid ducting and the minimum number of 90/45 deg elbows you can get away with.
A decent 6in inline duct fan, like they use for grow tents.
like this
Duct Fan at Amazon
I actually cut a circle in a 6 foot folding table I use to put the vent vertically and hold it into place.
I have it set up where I have to crack open the garage door, connect a section of duct to go out the door and put the fan on the end to suck out any potential residuals and I use a remote Christmas light switch to turn the fan on and off from my bench so it doesn't run all the time.
In the picture, you can see where I split the flow to have vents for me and my wifes' torch, sitting opposite of each other.
This works great for us and if your interested I can post more pics.