Bev grower - thanks for the advise on removing shoots, I am going to do as you suggest and let it have another growth flush before doing the culling, and possibly waiting to spring.
I have had both lemon zest and sweet tart - both excellent but I prefer sweet tart. Unfortunately, those varieties are too vigorous for me to grow. I have to keep my trees at 6' to be able to frost protect. That really limits which varieties I can grow.
That made the honeykiss not taking especially frustrating, since it can be kept small. Pulling apart some of the failed grafts, it looks like lack of cambium contact was the issue, some minor fusing, just not enough. I suspect the issue is my lack of skill in making the cut on the host tree to the right depth. For I can get more budwood I want to try that coffin/grave method rather than veneer. Didn't see that method until after I grafted, I think I could get a better take rate that way. If anyone has budwood they can share please drop me a pm.
Indigoemu - I have Pickering, Manilita, Maha Chanok & this cogshall I'm top working. As you noted it is essential to cold protect, or trees will be killed outright. That pretty much means limiting to varieties that can be kept small. Now that my trees are established all I need is c9 old fashioned Xmas lights to protect from light frosts. For a hard freeze I put up a mini hoop house over each tree - made of plastic sheeting and pvc pipe with a trouble light inside - those have successfully protected at 26 degrees for multiple hours and below 32 for 10 hours straight. If you search the cold protection threads I think some of my pics are still around of that setup. If I could only have one tree here it would be the manilita - it stays smallest and is most productive. The fruit is pretty and is consistently good flavored. Obviously can't compete with something like ST for flavor, but miles better than a grocery store mango.