So far, except for one variety, I've not had to thin any nects. They haven't set real well for me. It seems like they are more fickle to spring weather so far. Probably under good weather conditions, they would over set. We rarely get ideal spring weather conditions here.
Last year I spoke with a commercial grower who grew peaches for 20 years a couple hours drive south of me. He had a fairly sizable orchard (by Missouri standards). His orchard produced about 90 bu. per day during the season. He said of the twenty years he grew peaches, he had 4 years of full crops, 4 years of no crop, and all the rest of the years were partial crops. That's more or less what I've seen, that the norm here is more like partial crops because of the marginal weather.
It's during those partial crop years where I see the most potential to move the productivity. In the 20% of the time there are full crops, variety doesn't matter, since everything will set full crops. In the 20% of the time when there is no crop, variety doesn't matter because pretty much everything fails. The rest of the time (marginal years) there are varieties which still set full crops, along with varieties which are pretty much blank. I'm really working to try to identify varieties which are still productive in marginal weather, and taste good, and don't suffer too much bac. spot.
As an aside on the bac. spot issue, last winter I got rid of a lot of my worst offenders for bac. spot (mostly white varieties) and I seem to have seen less bac. spot this year on the remainder of the fruit trees. This is just the first year since I removed so many bac. spot prone trees, so it's a little premature to draw any confident conclusions, but initially there seems to be less bac. spot in general, despite some really rainy wet weather in early summer.
There is one variety of nect which sets very heavy, Hardired. It sets heavy, but even when thinned properly, the fruit are much smaller, so the yield is lower.