I don't see a big difference between the LM317HV and TL783 circuits here. Both are a linear HV regulator so heat is a big concern.
The TL783 circuit 120V zener just means most of the heat will instead be dissipated by the TL783 now. The TIP150 drops voltage when things are over 120V input-output. It's also a small, obsolete transistor compared to MJH11022.
The LM317 circuit was the opposite with the 6V zener, it let the MJH11022 dissipate all the heat in dropping the voltage down.
Check the thermal calcs, 1A output and 140VDC input is still 15W of heat and a large heatsink for that to rise say 30-40C.
I still question the need for a voltage regulator with solenoid loads. They can take +/-20% variation and a decent sized power transformer will "regulate" close to that. What's wrong with using a 90VAC transformer and bridge rectifier only. I find 125VDC is only used in railroad and utility substation applications.
Note also there is a liability due to the shock hazard with the high voltage going outside the product.
I would increase the safety of the output connectors and field wiring. Make them touch safe at least.
Banana plugs might not be insulated well enough for lay people to mess with them.
I was thinking of using 3 copies of that circuit, so each should only see the 280mA for its dedicated output.
I'm not set on regulation or that circuit, I would be quite happy to not need "active" circuitry.
But I do want to limit the output voltage pretty close to 125-128VDC.I am not having good luck finding 90VAC transformers in the 120-150VA range. Found a 100VA with 90V tap,
Hammond 169C, but that would be running at a slight overload (I think?) with all outputs on.
I would really like to use an isolation transformer as opposed to a standard one, although I don't know how major the differences are.
I am also concerned with the output voltage running too high, the above transformer is spec'd for 115VAC in, our mains voltage is 120Vac generally, 125Vac in some areas.
After rectification and filter cap thats 127VDC (which is fine), from 115VAC. 90V*1.414.
Unless I am screwing up my math(probably)
125Vac is 8% higher, so the DC would be 137Vdc. I am somewhat uncomfortable with that.
Although I don't particularly care if the voltage is lower, currently the "working" unit drops to 100VDC, and they didn't notice apparently.
I don't want to go that low, but 115-120VDC may work.
So perhaps a 80-85V transformer, which seems even harder to find. Or perhaps a second transformer in a buck configuration to trim the voltage to where I want using a easy to get main transformer.
Efficiency is not a priority.
After thinking some more I am liking the idea of: isolation transformer, with an additional buck transformer and then bridge rectifier/ filter cap.