Mike, I'd start with a few slits... 2-3 and check the air flow out the slit near the top... You should see some "wafting" of the smoke coming out... That's a good indicator of nice air flow... I'm totally guessing here, but about a smokers worth of air change about every 5-10 minutes... How's that for being technical.... Just enough to remove moisture without removing too much heat....
About the sketchup.... I looked at it... downloaded "something" and decided my pencil and paper and my scanner were technical enough for me at this time.... If I spend any more time at this computer, the History/Discovery Channel will be after me... HAHAHAHA... And my neighbor will wonder why I haven't welded up his broken stuff...
You can put something on the slits to close them up... no problem.....
Dave
About the sketchup.... I looked at it... downloaded "something" and decided my pencil and paper and my scanner were technical enough for me at this time.... If I spend any more time at this computer, the History/Discovery Channel will be after me... HAHAHAHA... And my neighbor will wonder why I haven't welded up his broken stuff...
You can put something on the slits to close them up... no problem.....
Dave