To start, I would not project the slide unless you absolutely have to. The dyes in the film are very stable (especially if it's Kodachrome) but why tempt fate? I have seen slides burn up in there and more often seen dust bake right on the image.
Second, I'd make sure the slide is clean and free of any finger prints. Storing it in an archival sleeve is a good idea
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Lastly, rather than buy a mediocre film scanner for one image, I"d send it out to a reputable service bureau for a repro quality drum scan. If you want a suggestion pm me your general area and I'll find one.
Congrats on your new acquisition.