Just an update on this. After failing to produce queens, my mating nucs wouldn't get back in gear (in short time), so I shook them out. After a few days I pulled brood frames from a swarmy hive to rebuild 4x 2-frame nucs. I left them for a few hours until they started to roar, then grafted cells. My previous attempt at grafting was only about 40% accepted (though all were lost due to a mis-step of mine after). This attempt was 75% accepted (6 of 8). I consider this amazing considering the conditions!
I have a habit of making things harder than they need to be. I had a schedule set out and decided I needed the grafts in Sat or Sun this past weekend. The forecast for Sat was spotty showers, and Sun was full day rain and storms. I decided then I HAD to do things Sat. I pulled the brood frames in the morning (around 10am) during a light mist. The bees were flying and didn't seem to mind. The hives are under tree cover, so they weren't really getting hit from this. The day cleared up a while and after lunch, I pulled my donor frame and grafted cells. I cut strips of pollen patty for the nucs and prepped syrup w/ HBH to keep them going strong as they build out the QCs. Just as I started to place the cells into each nuc it began to rain a bit. I leaned over the nuc to keep them from the direct rain, though they were still taking on water. By the third nuc it went into a full downpour! I knew I had to get these closed up, but also didn't want to toss the new grafts, so I rushed to drop the cells between top bars so I could just go. They got more water in them than I'd like in the process, and the patties were starting to melt in the rain. Disaster! Sunday provved the weather man to be wrong by being warm and sunny, a good flying day. I pulled open the nucs to see just how bad it was. The cells were being tended to and drawn out, even those sitting across top bars. I carefully pressed each good cell (6 of 8) into a depressing in each frame. The bees were enjoying the softer patties and eating them at a pace I've never seen before. This may be a new technique for me (moistened patties, not grafting in the rain!) I was glad to see there were only a couple dead bees in the nucs, not handfuls as I had feared.
I hope I never have such an experience again, but it did show me that while sensitive, the grafting process is far more tolerant than I had ever understood from any book or forum post! For anyone that hasn't tried it, it's not that scary. :) Also worth mentioning, I have a chinese grafting tool that works so-so for me, but I've found better luck using a paperclip with the end flattened and slightly curved. I now use the chinese tool occasionally to gently push larvae off the clip, though usually this is not necessary. Also, any time I find queen cells I remove them and collect the jelly, putting it in a glob in a bottle cap which goes into the freezer. When grafting, I let one of these warm, and moved a small amount to each JZBZ cell cup prior to grafting, not so much to cover the bottow, but around 60-75% covered, and deep enough that the flattened paperclip could dip into it a bit. While grafting, this allowed the larvae to easily 'float' off the tool. I suspect though that my failures might be due to sticking on the tool, causing them to dip too deep in the jelly.
For those that graft a lot, I've always ready to use just the tiniest minimum in the bottom of the cup. In my experience, this was not the case. Since using jelly, wouldn't it give them a head start to feeding the cell? Also, might it be possible to go even further, filling the cup half way or more, giving the larvae all the food it needs, with the bees only needing to cap the cells?