After charging and testing the three batteries, I determined that one of the older (dated 11/1
batteries was no good. The other two charged, stabilized, and tested ok under load.
The consensus seemed to be that all other things being ok, that two batteries of slightly different CCA would be ok. I cleaned all connections to shiny metal and reassembled. The bus started right up and was charging the batteries at 14.3v. I did not have the jumper cable to install the battery disconnect, so I left it with negative cables disconnected. I'll do that next.
I appreciate all the help.
Joe