I just finished installing a Lewmar Pro Fish 700 on my Islander. Works great. I love the free drop feature and be careful the first time you retrieve the anchor, it comes up faster than you would expect.
Buy a high quality 3" hole saw and take your time.
Your rope locker space is very limited on the Islander so I used 300' of 8 Pliat line with 15' of 1/4" chain and fed about 100' through the anchor locker drain hole into the compartment housing the hot water heater. Tied a hugh knot in the end so I don't lose everything.
Snaking the wire from the battery compartment to the helm is a bit of a trick. PM me if you have a problem and I'll explain how I used a Shop Vac and a 4' piece of 1" PVC taped to the hose to fish out the nylon cord I taped to the end of the wire.
Check Lewmar's web site and download the operators manuel. The wiring diagram is color coded whereas the directions that came with my unit were not.
You are going to need another small hole saw to mount the switch. I mounted mine to the left of the steering wheel so I could run the anchor and operate the controls/steer at the same time.
I used #6 AWG wire and went from the negative battery post to the helm. My positive lead came from the battery switch so I could shut everthing off when I leave the boat. I mounted the circut breaker on the bulkhead next to the battery switchs.
Good luck. If you have a problem PM me your phone # and I'll give you a call.