I did install same
windlass on my boat some years ago. Although your idea to use the panel DOES work, it don't provide enough safety to isolate the entire system. It will work as a "convenient measure" to avoid accidental operation, but will not isolate the system in case a failure. So, with such arrangement, you should have the 70A braker also in a handy location for an emergency, and you'll need also to toggle it off when you leave your boat (if you wired directly to the engine batt). That just seems a double care to me, and could fool you when needed to cut the system. I decided to install the breaker just aside the panel on nav station, so I can reach a SINGLE measure to isolate the things.
Another observation, I did also run a switch on helm station, and found it very usefull when docking on
anchor (mediterranean style). But, for many (and I mean many many many) times I had problems because I used it to drop and pull
anchor in regular ways. Mostly times, my chain got clogged and I didn't not "hear" it, I kept pushing the switch and made things worse. Other times, I was pulling
anchor and crashed it on my pulpit as I couldn't "hear" it reached the deck level. Since I could not educate myself for the proper usage of helm switch, avoiding dangerous use of it, I decided to have bow only ones, and trust more on visual than my ears.