Hi There

Firstly yes i would run the tube parallel to the bottom of the boat, but slightly raised before it exits the transom, say 4-5mm above the bottom of the transom on a boat that size, also offseting the stuffing tube slightly to the right (say 2-3mm on your sized boat) will elimate prop torque, raising the stuffing tubes exit helps cut down chine walk. If your boat is setup 100% correct, it should not need trim tabs, they are a way of extending the hull slightly but otherwise its a bandaid fix for a boat that size... no trim tabs will save clutter and weight, I spend a lot of time setting my Mono's up and dont use trim tabs, unless the hull has a fundamental flaw you can do plenty of trimming by mocing the batterys and changing strut angle, theres an article by John Finch around somewhere called "Mono Mania" its worth a read for mono setup...

Peace