Hi guys and gals, After doing strictly large format and contact prints for the past couple of years, I've started also using a medium format rangefinder. So, I'm now setting up my almost-30-year-old Beseler MX-II with my equally-old Aristo cold light head, which still works, remarkably! My problem is that I can't find the plexiglass diffuser that sits beneath the tubes of the cold light, so I need to obtain or make a new one. I've never worked with plexiglass, so... do I just buy a small sheet of 1/8" plexi and cut it to the (square) size I need, then cut/sand the corners until it's round? What do you use to cut plexiglass? TIA for any advice you can offer!