Thanks for the links, I'm reading them over now.
I find that with the print widget in Chrome and Firefox sometimes I get the output I expect, but often I don't get any output, and looking further I see there are CORS errors there - odd that it's sporadic, but I'll try to get the server-side CORS support and/or proxy installed on this end.
I do get a laundry list of errors in all browsers when the viewer loads, but I had been ignoring them to this point since it was functioning as expected. If you think they're relevant I'll post them, although please let me know if another thread or space would be more appropriate - I'm also looking into our organizational information for calling support.