This discussion is interesting. I have been through all that motor in a well stuff with my NIS26 and perhaps you might be interested in my findings.
Closing the well bottom while sailing is very desirable, from a noise point but also drag with my boat as the openings aft end does tend to scoop water if I'm sitting at the helm.
Travis's well opening is, IMO, far too wide. It would benefit from a lip all way around so a well closer can be fitted. The opening only needs to be just wide enough to clear the prop diameter.
My motor lifts on vertical slides so I do not have the tilt room problem, the well closing board slides athwartships in alu channels. It is operated via pull strings and a push stick from above. There is a 45 deg bevel on the fore/ aft sides of the well opening and a matching bevel on the cover. This stops it from popping down beyond flush with the boat bottom. I drop the raised motor skeg onto the shut cover to stop water pressure trying to push it up.
The comments above about the tell tale water exit under the cowling are unfounded, the warm water just sprays onto the well side and exits at the bottom. It is only a small part of the cooling water anyway, the major part leaves through the exhaust hub. I never had a problem there.
The relief exhaust hole near the top of the leg did cause a smoke problem in the well, I fixed this by fitting a hose barb fitting to the hole and a hose from there out the transom. No more smoke in well while motoring
now.
I should mention my motor well is completely enclosed and if I have to motor some distance I close the front access hatch too, to shut in the two stroke noise. The well has large air exit vents on the transom and two computer fans ( brushless) blowing in fresh air through hatch grilles.
I have rigged my motor to steer with the rudder and it made a HUGE difference with marina manouverability. My boat can now claw off sideways off the ramp jetty without having to gather sufficient way first for rudder steering. I can also motor in extremely shallow water with the rudder blade ( vertical drop kick type) down at minimum draft. Motoring in reverse is no longer a tiller slamming hard over affair.
Linkage motor to tiller is via ropes and pulleys from a hook screwed to the aft end of the motor cowling. It automatically disengages when the motor is raised, removing the extra tiller load of the turning motor.
I have completely removed the motor tiller handle (so the power head can easily turn inside the well, I get + - 30 deg) and now operate the motor via home made morse control.This motor ( Mercury 9.9) had a combined throttle/gear shift arrangement that made this task relatively easy.
Klaus