HI Dana, thanks for your in depth reply. I have solved the problem and the printer is working perfectly now, but will address the issues in case it helps anybody else coming here looking for solutions.
I took the damper unit back off, made sure the new k ink was flowing thought the line and damper by drawing more through by syringe via the damper output point. This has to be done very lightly to avoid damaging the damper, I assume. The other point here is ink must be freely available so the lever must be in the locked position, but pressure relieved from the lines by momentarily removing the plugs from the carts on that side. Otherwise, an ink mess will occur from all four at that end, or if levers in the unlocked position to avoid a mess, the ink line is closed and drawing ink through a problem. These are my observations and are open to correction. Also, while the dampers were off, I injected your purge fluid through the K nipple of the head, let it sit, and did that a few times, in the end pushing it through. I had a small plastic garbage bag around and underneath the head, going down through the paper path, to collect the fluid. The I reseated the damper unit, started up, I immediately had good K channel nozzle checks, and the others came along quickly as they were simply without a little ink from the damper removal. Just a few normal cleanings and a little sitting time, turned on with pressure, brought it all back. After rethinking everything and the hours into this, my suspicion is that the problems was lack of a good seal when I seated the dampers from the first repair, but I could be wrong. I had a hard timer with re-assembly and I think it wasn't sitting just right. Anyway. just for thoroughness here, I'll answer your questions-
1- before the damper replacement, I began again with a new cartridge entirely, with some purge in it, and drew some through the line to clear it of the old ink. Then filled the new cart with the new ink and began the damper replacement.
2- Yes, before breaking it back down again, I did normal cleanings, deep cleanings, and SS cleanings, over the course of about 24 hours, nothing brought a single nozzle back.
3- I don't have your kit but it sounds like I accomplished the same thing above.
5- The damper replacement was the result of an ongoing issue and several emails back and forth over a few months. I was having some problems with my K channel, and this did fix it, but that was not what instigated the damper replacement. There was some question about an ink batch, I think you are familiar with it, it's solved. It wasn't the ink itself.
6- Yes my nozzle checks before the damper replacement were good, usually perfect, but I had other delivery problems with the channel, which the new damper fixed. Again, I had no fatal problem before the damper replacement, not one that initiated that repair anyway, it all came about as a recommendation from our friend Wells to make sure no problems developed from previous bottles...
and in the end, now that it's working, and my other problems with K resolved, it was a good call despite the repair problems. Hope this helps-