Nice job, it looks great! I went overboard with my build and ended up with a bunch of stand offs and mod holes. I like the simple solution here. It lacks some functionality but makes up for it in simplicity.

It seemed to me a very simple solution was possible, and thus, this design.

Small, light, uses very little filament, prints up quick.  (Though I found printing them one at a time did better than trying to do six at once, but I bet you guys are so much better at SD3 printing you could do it with no trouble.)  Then I just krazy-glue three of them to a piece of plexiglas and it mounts easily.

At the bottom, the plexiglas hangs a little bit away from the frame, but you can easily use magnets to address that, to get a better heat-tight wall.  The magnets don't need nearly as much strength to make the sheet "stick" to the frame as they do to hold its weight up vertically.

It comes off when I need to get to the innards; the clip is just enough bigger than the frame to let it slide enough to do that.

If you want to use this for your SD3's front, you'll need to cut or drill some holes in the plexiglas to accommodate the ends of the axles and the mounting screws (I'd already done this for the magnet version anyway), but I have chosen for now not to do this for the front, since I need to take that one off far more often (to put new glass beds in and get print jobs out), and the magnets are holding up fine there (since those holes also help hold up the weight).  So I'm only using it for the sides.

No idea if this will fit an SD2.  I assume the frame isn't exactly the same size.

If you try it, please post an I Made It on my Thingiverse thing page, as I've never had one posted before and it would be nice to see.