I got some more batteries from the boat place. I decided that the Group 27 batteries would be a better match for the Corolla, and I wanted the smaller Group 24 Marine batteries for the Geo. Here they are:
Also, I decided that I couldn't trust the resistance readings I was getting from my old cheapo analog multimeter, and I don't understand what the Harbor Freight one is telling me, so I broke down and bought a Curtis PB-6. Well, actually, the part INSIDE a PB-6 that everyone is buying at Radio Shack for $2.99.....
So that way I can check and see if my TPS is working right....