Howard, if the main thing you're concerned about is protecting the usability of the ink switch in the damper, it may be better to use it periodically than to leave it fixed in one position forever. As for the papers, based on the ones I've tested, luster and satin finishes are the less glossy of the gloss types, but they all use PK ink, and the "fine art smooth" matte papers are the least textured of the mattes, but they all use MK inks. I think it's probably best to use ink and papers in their recommended configurations and not worry about the effect on the damper of ink switching.