when you drill the whole, round the edges, dont make it like a perfect square-more of a circular. and also take that dremel and grind down the outside edge to make it smooth at about a 45 degree angle. just go slow and PRACTICE, you dont wanna f-up a perfectly good case. and while your at it, draw a circle in teh plexi and cut out a fan. or two;one on each side or even four if you gots-ta. If you take pride in your work, dont glue the plexi on, take your time and drill some holes and fasten it down with 4-8 screws. but dont tighten a screw directly onto the plexiglass, use a plastic washer(if theyre made-just and idea) i dotn know if they make them but it would be a good idea to put something hard in between the screw and plexi.
yeah...use goggle...i was making a litle wooden car once and didint wear goggles and a few small pieces of metal flew into my eye, took about a week of putting this cream that resembles spooge into my eyes every night *shudders*
just take your time, and focus. recheck all your measurements and everything before you start hacking away, dont want a lop-sided window.