I don't understand why the outer batteries would degrade faster if they are getting the easier ride. I would still be bringing each pair to 100% separately whichever way I do it.
The pair of 12s right now has the highest capacity at est 243, with the Interstates at 232 and the Exides at 226.
( I don't know why the Exides don't like this routine I am on. Maybe they spend too much time at 14+ volts on solar. smk is always going on about too much time in the controller's absorption stage for storage. The controller is timed for two hours, but while camping and running high amp loads after dropping to Float, it keeps getting knocked back into Absorption for another two hours. The Interstate GC2 XHDs love it though)
The 12s are now wired up in the centre position, and my pos load wires won't reach farther out, so the easiest quick job is just link a pair of 6s on each side of the 12s.
Maybe work the heck out of these 12s and then toss them and go back to my four 6s like nothing ever happened?
So far, I can't tell the diff on the two 12s from the four 6s. They take inverter loads like the kettle at 90a no prob. eg. I will get them back up to "full" and then switch off solar and run them down to 50% est again and get another est capacity.