Hi--we have a deep undermount sink--the strainer basket hangs down lower than before. I have a double bowl sink that would need some sort of "T" fitting, and I need a "Y" fitting for the dishwasher. When I stick these things together on top of the trap, I have run out of vertical space. The trap is lower than the drain stub on the wall.

Can I run the dishwasher "Y" horizontally, as long as the output faces towards the drain? Can the "Y" be put horizontally between the trap and the wall?