Here's the link I promised: http://modelpaint.tripod.com/booth2.htm
Sometimes the page works for me, sometimes it doesn't. It isn't meant to be the last word, just help.
I'm not an expert and don't mean to sound like one. All I know is what has worked for me. I was in the same situation about 5 years ago. Except for the girlfriend. Small apartment and wanting a paint booth. Mine isn't what I would have liked to build but is the best I could do at the time. I would have liked to use sheet aluminum but no longer work in a sheet metal shop and don't have access to the tools. So, I built mine out of wood. Or rather, a friend with a work shop took my drawings and built it for me. I used white latex interior paint. If it gets too grungy, I paint over it. I don't line the walls and floor with newspaper or anything else, that's just another source of dust and lint. I built it with the fan on the back wall. Didn't want a downdraft because I wanted full use of the floor. Didn't want an updraft because then everything has to bounce off the back wall. I figured with the fan in the back I would get better exhaust. It worked for me.
I built it to use furnace filters. There's a small door on the top that I can lift and drop in a filter. Lately I've been using some industrial filters that a former employer gave me when they changed to a different air handling system. The top is a sheet of plexiglass to let in light. I added some 12" flourescent fixtures I found at WalMart that can be linked together. There's three just inside the door, right left and top. I used some small, screw-in hooks in each top corner and ran wire between them to hang things from. Bent pieces of coat hangers to make small S hooks. There's a door on the booth so when I'm done painting I can close it up keep any odors inside and dust out. Inside it's 16"T x 16"W x 14"D.
Now, the fan. I was right on the verge of buying a fan like the one you mentioned. Had it in my hands at Home Depot. When I got to looking at it I realized the frame was fairly loose construction and there was no good way to attach ductwork. There were some with a hood of sorts that would connect to a 4" pipe but they were a good bit more expensive. I waited till the next day and asked my employer if I could buy an item from Graingers through them. Then I ordered a 4C447 Dayton blower. They're basically the same price I paid 5 years ago, $64. I misspoke in an earlier thread and said I used a 365CFM blower, this one's top rating is 265CFM.
Who am I to say that someone else's set-up doesn't work. If it makes them happy, that's fine. To this point, I've used solvent based paints. Enamels and lacquers. The blower I use does a good job. If I had it to do over, I'd go with another 100CFM. Something like the 4C444. I really can't imagine anything 100CFM or less moving enough air in a booth the size of mine to clear the overspray and fumes. This booth will handle aerosols which put out a lot of overspray. So, I guess you have to ask yourself do you want something that will clear the room eventually or, something that will clear the fumes and overspray as you paint? I went with the latter...
Also, I've managed to keep the booth close to a window so I just use flexible dryer hose for ductwork. The aluminzed type, not the thin plastic. If you have to be more than a few feet away from where ever you vent to I'd suggest using rigid ductwork to reduce drag. The blower I used is a simple two wire hookup. I just used an extension cord and cut off the female plug. I used an inline rocker switch like the ones you can add to a lamp. I'm no electrician but the amperage draw on this blower is pretty low and this cord's never been a problem. It's run for hours on end and never gotten warm. It isn't loud either. Can't give you the decibel ratings but it's in the neighborhood of a bathroom exhaust fan.
So, there it is. What I did and my opinions. It works for me.
Tony