I have two questions about grout. I have 12x24 gray tile that i want to place on the kitchen floor in a 50/50 offset.

#1 i cant decide whether to use slightly lighter gray grout or a grout with the same color. Im going to have very little gap between the tiles

#2 since it is the kitchen i want to use an epoxy mix grout. If i use a darker grout do i even need to use epoxy? I figure it is good for stain resistance.