It makes good sense as someone mentioned. There's a lot of potential you will work on the cable connections to the starter and connected circuits back to the alternator. Short circuits do happen(we had one and a fire).

We have a dual output alternator so the secondary charging line goes to the starting battery.

I simply kept the old 1-2-both switch on the house. It's pretty ancient but seems to work fine. The added starting switch is ON-OFF with an 18" cable between it and the battery.

I use one of those combination starting/deep cycle batteries. I like it as I raise most of the rode and chain, clean with the deck wash, without starting the engine(all functions powered by the starting battery) No problems, we're way over batterie--d, and sometimes sail away from anchor. My starting batteries-way outlast- my house.