I've made a few more measurements and a few more changes.
1) All transformers wired at 220, confirmed in phase, no wild leg.
2) I removed the green ground wire on my transformers, as suggested by MEP001. Confirmed that there is so difference in any volt/amp readings anywhere, as expected.
3) I had a couple 5A MDL fuses, installed them on 2 transformers. Hardware store didnt have 4A, I have some on order. Life in the country
4) I confirmed the amp readings on the hot wire coming into the timer on all functions, all bays except Bay5 which is where I've had most of the problems - I've been nervous about opening that bay back up until I get this issue sorted out. I think I'm getting it sorted out so I will be reopening & running tests on that bay shortly.
(Note: Construction on the road in front of my wash for the past 3-4 weeks, business is way down so this is actually not a bad time for me to have a bay closed and be doing all this "experimenting.")
All amp readings are within a few hundredths of being the same, and dont vary. So I'm tentatively concluding that I dont have solenoid issues.
5) Incidentally, I observe that the EV timers and the dixmor timers pull about the same amperage when in use (within a couple hundredths). When rotary switch is on stop, the dixmor varies between .2 and .15, whereas the EV varies between .22 and .32. I speculate that the variation is due to the scrolling led message differences.
6) I measured resistance from the mounting plate to the grounding lug, 55 ohms. A 12ga grounding wire that goes directly to the grounding lug measured 22 ohms. I'm not certain how material that difference is, but at least it tells me the mounting plate is not as good a ground as a wire going directly to the grounding lug.
you're not going to see 24V if you take a reading from the transformer to the ground because your transformers are wired at 220. EACH OUTPUT from the transformer will read 12VAC to ground.
7) Hmmm. With my transformer wired at 220, I disconnected ALL wires & the fuse from the 24V side. One terminal measured 27V, the other three measured 0V. That leaves me wondering why 2 of the terminals are wired together, but at this point I'm getting a bit saturated so I'm going to chalk this up to "different transformers behave differently" or something.