We're painting the kitchen in our new house, and we currently have an (awful) tile backsplash. We're painting the kitchen BM Raccoon Hollow, but are going to use Sherwin Williams paint (there's a 30% off sale right now). We can't afford to redo the backsplash (and terrible countertops) right now, so a decorator friend said to just paint the tile for the time being.

I know we need to sand and prime it, I'm just wondering if you'd suggest going with a high gloss finish on the backsplash and then a regular finish on the rest of the walls. Usually I'd use a semi gloss for the kitchen, but in this house the kitchen is attached to the dining room (sharing a wall), so I thought I'd go with more of an eggshell since I don't want the dining room to have a really glossy finish.

I attached a pic. We're also going to paint the cabinets white (eventually) which will brighten things up.

Would another option be to use the same paint for the walls and tile and then just to put a coat of polyurethane on top? What do you think would be best?