1 Guage Starter Cable v. AWG 6 Boat Cable

[Gone2long]

Ok cable guys, here's another dumb question,

I want to wire a 3rd battery to my house bank, but I am not sure if it is OK to use wire I have on the boat.

My house battery bank is wired with AWG 6 Boat cable and I have not been able to find any for sale in the SE Asian nation that I am in.

However, I do have some " 1 Gauge" Belden Starter Cable aboard. Would it be OK to connect my third battery to the bank using this larger, 1 Gauge wire? I assume that the only disadvantage might be the extra weight.

Also, I think that the "1 Gauge" designation refers to the BWG or SWG system; Does any one out there know? Seems like, if it were AWG, it would read "AWG 1", not "1 Gauge".

Lastly, anyone know anything about "Motolite", maintenance free auto batteries? I know, I know, I shouldn't be using such batteries on a boat, but, once again, nothing else is available where I am at the moment.

Any problem putting an "Excel" battery in a bank with two "Gold" batteries? Supposedly, both batteries are rated at about 70 Ah, and both are the same size and approximate weight. The Excel is supposedly for use in "ultra duty" pickup trucks, while the Gold is supposed to be for "high performance, foreign made (meaning Korean or Japanese) SUVs".

Anybody got a clue?

Thanks again,

G2L