+1 for Capt J's remarks about Tides and PSS. If it was ever my money; I would buy PSS. I put a set on a 1974 Chris 68' Roamer that had badly...
The reason to not use SS studs vs bronze is simple crevice corrosion. If the SS studs are wet in the hull, they will simply waste due to depleted...
You might try Gemeco for real-world solutions for Maretron. They're the major East Coast distributor for all things transducer, Maretron, NMEA...
There's some info on Active Captain for the area. There's a Wal-Mart and at least two restaurants on the water nearby. I don't know the area, but...
Brush? I'm not he most experienced polisher in the world, but I've had many opportunities to critique the field. First detailer I ever met worked...