The tile is the usual thickness; the granite is about 3/4-inch thick,
so the trim piece idea would be just fine. I just am stumped as to what
would "look" OK to cover the tapering gap that is about 5/16-inch max.,
with drywall showing.

maple cabinets
black-gray-green granite
white tile
stainless sink
white appliances
under-cabinet track lighting

-Gary