Hi Zcot,
Welcome, I am also a noob to earlybay, but am returning to the VW scene after a long layoff (15 years) You're thoughts about connecting two batterys together + to + and - to - reminds me of a generator failure years ago on our bus the night before we were due to set off for a 2 week surf trip to Ireland. At the time I worked for a Tyre company and we ended up paralleling up 3 massive tractor batterys borrowed off the company in the old bus (took out the cool box of the dormobile) ended up driving 2 weeks around Ireland without charging (disconnected the generator and ran off the batterys) - so it can be done. Make sure to use cable of correct rating (great big stuff) to connect all the batterys together. All that happens is that, in effect, you add the AH ratings of the batterys together. Seem to think, if I remember rightly, we ended up with something like 900 AH!
Todster