I have a mat cutter, so I cut my own, I like at least an inch around myself. If you have the room for one, it’s pretty useful.
I don’t know that there is any solution really. That cut out is too big for mats that size.
You could glue use glue instead, the kind of glue they use for scrapbooking that is archival and removable but that would wreck pastels where the glue sits, probably wouldn’t be great for watercolor either.
Or you could if you’re framing it, not use tape at all but put enough paper behind the art that it is held in place by the pressure of the frame backing.
Hopefully someone else will have an idea too.
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