I've seen that set up, (fan in the window) cause an explosion before at my friends home. Just a word of caution.
The way a safe setup is accomplished in a spray booth is the fan blades are turned by a belt from the motor that is outside of the spray room. The blades are in a duct sucking the air out. Even the light fixtures are outside the spray room or booth. They are behind glass panels that are sealed air tight from the spray area so the fumes cannot be ignited by a spark!
Spark from electrical motor of fan plus fumes of paint if just the right mix with the air go boom! My friend blew the roof and front wall of his house off 75' across the street and he hard burns all over his body. I know he was lucky to survive. It scared me because I also was painting in a make shift spray booth. I had created a spray area with plastic sheeting which is another No No. This is because of the static electrical spark igniting the fumes. But that's another story. My friend had been spraying many years like that until that perfect balance of air and fumes ignited and ruined his day. Something to think about my fellow modelers!
I have also seen it happen to a second friend that was spraying in his garage with the garage door open and the pilot light on his water heater ignited the fumes and boom! He was also burned over 80% of his body! I saw him a year later.... he was 6'4" but now is about 6 inches shorter after all the tendons contracted from the fire and his skin, well what's left of it...let me just say it's disturbing to look at.
I really didn't want to write this but my friends wanted me to warn everyone so what happened to them would not happen to anyone else.
On a happier note... Great job on the Pitts!.. Robert.
Take Care
Don