Any of the three major sprays (Moab, Hahnemuhle, Premier Art) will, with multiple layers, protect against fingerprints and some light water contact. I usually apply three light spray coatings. For greater protection apply a heavier water based coating like Breathing Color's Timeless or Premier Art's Eco Print Shield on top of the initial spray coating (you have to varnish spray coat the print first before applying any water based coating to keep the print from absorbing the water and warping).
+1 regarding the solvent based sprays.
I use 4 light Print Shield coats on satin paper. So far, none has suffered any damage in display. I dry mount the prints and do use a 1" white border and minimalist black wood frame. Then when people grab the display print at the top (and they do, regardless of advice to use the back wire), they are not touching any of the image surface. In a recent show (still up at the Elverhoj Museum in Solvang, CA), people noted the better look of the un-glazed, sprayed prints compared to the more traditional matted and glazed prints that were also on display. While the decrease in accessible dynamic range of the print can be minimized by using coated Museum glass, that is expensive and not readily available to many sizes. Also, particularly with my black and white, the museum glass has a purple reflection that is annoying.
My experiments with the water based coatings were not very successful for prints larger than 8x10". Among other things, isn't one of the goals to lock up the water-absorbing parts of the inkjet coating? If so, does applying a water-based coating make sense? I would think making sure the print has dried thoroughly at least overnight, and then locking up that coating with an acrylic spray makes a lot more sense.
Paul
www.PaulRoark.com