I just completed a re-wire project on my Compac 23 this past year. I added in a new house bank, an extra fuse panel, and all new wiring.
I upped my house bank to 2 gc2 batteries wired in parallel (2 6V batteries = 12 Volts) which gave me a strong 215 Amp Hours. The batteries run the ground directly to a ground bus bar and the positive runs to a battery on/off switch and then to a positive bus bar. The bus bar has two wires that run off of that to the two fuse panels.
Don't cut corners on wire, wire connectors, etc. Get good stuff so you won't have to worry about it or do it again (Marine Grade). I got the crimp and heat shrink connectors and I won't regret it.
It isn't a bad project. Some of the wire runs can be a pain because it is tough to get to them.