Re: EMS gauge removal
The wiring connections are at the back of the instrument so look for access there. There is usually some sort of clamping/securing devise on the back, once you expose it should be a screw driver and not much else. BUT, beware of the siliconed in place face, so you might need to get behind the bulkhead flange on the instrument with a putty knife or similar.
Teak makes a good cover if you are ok with maintaining the teak, and you should be able to screw from behind to secure. With the Hunter 23 being mostly molded FG instead of a lot of exterior wood 1/4" acrylic might also work and eliminate the maintenance. Filling the holes works, but expect it to weather different than original.