[DelmarRey]

Owen,
I really see your problem here with the motor being right in the middle of the solon.
You always want to eleminate as mush back pressure as possible. It can burn and /or deposit up the valves.
As for the lift, the exhaust thruhull is usually a few inches above the waterline. The riser loop from the lift only needs to be above the engine exhaust manifold but at least 18" above the waterline. It must run down hill from the top of the loop to the thruhull. And the lift itself should be at least 12" below the manifold outlet, or the loop in the exhaust outlet.

There are several ways to install a wetlift system. The main thing is you need to know is where your exhaust mainfold is in relation to your waterline.

If it''s above, that makes it easier. You can put the wetlift closer to the thruhull and less loop.