Before you make your bulk purchase, maybe try out some of these methods on a few prints and see what suits you? I used to frame and mat prints myself, but the reflections in the glass and plexi was beginning to drive me crazy. Can't see the image clearly lots of the time. Now I simply mat them and display them w/o frames or glass and they looks fine. They're not watercolours, they're B&W prints, so I wonder why covering photo prints w/ glass became such a thing? While glass or plexi may cut down on fading due to IR, if the prints aren't in direct light or very bright artificial light there should be no issues.
Back in my inkjet days I would print on these beautiful textured papers, and as soon as you laid glass or plexi on top of the prints the texture would just disappear. That tells me the glass or plexi is disrupting the light and not showing what is really there on the print. Not good!