Put some tape across the back of thetransom at the level of the cockpit sole. mark the locations oon this tape for the proposed starboard and port ingress drains
mark the locations for the proposed eqress drains with two more pieces of tape on the back of the transom.
Get a protractor. Imagine the boat is heeling 10 degrees. Line up the long horizontal piece of tape with the 10* mark on the protractor and the center of the protractor on the ingress drain location. Will the egress drain be below the ingress drain at 10* of heel. Check again at 20 or 30 degrees of heel. How much heel can you accomodate by moving the drain?
Last point - smooth, wire mesh reinforced, chemical resistant hose is what you want to use. That way stuff doesn't get stuck as easily in the hose, and it can't be pierced by junk rattling around in the back of the boat. Also won't deterioriorate if you spill gas or oil...
Best,
Judy B