I own one of the Perko lights that you linked to, it is in my Boston Whaler. It is nice but I am not sure its worth todays price.
On my M I have a
http://store.hamiltonmar...t-ss-135851-/4,383.html which is a pretty good light for less. I cannot use it from the lower helm because of course the flybridge is in the way, so I use it manually on the flybridge. It is mounted in front of the seat, and I put a handle and switch on the back of the light so that I can use it directly. On an M without a flybridge, it can be mounted as intended and used from the helm.
I have no searchlight that I can use from the lower helm. I don't know how to fix that...
1975 32' Flybridge Sedan, twin Perkins 6-354 diesels, 1:1.53 velvetdrives, 16 X 19 props. Merritt Island, Florida