For years I did 88.6. Don't know why. Last year I changed to 87 because I had a shot at caramel and one of the many mythologies of how to avoid kinks in caramels is lower incubation temp (and I was willing to try them all, including rubbing a rabbit foot if I thought it might help). I had some regulation trouble with a new incubator and background temps in an out building but had a good hatch with only one of three caramels with a very slight tail tip kink. My stripes weren’t the best and even though I’ve received feedback that temp doesn’t matter I’d like to try them warmer next year. I did have one missing eye baby out of 70 or so but might have just been a fluke. Anyway, my point is I think they are tolerant of a fair range. If I come up with the money to switch my rack over to more zones with proportional thermostats I might go all maternal this year except for one cool artificial incubator for caramel and one warm end for stripes. Of course if I get good results it will not really be scientific since I’ll not have enough or want to try some cool incubation stripes and hot incubation caramels. That’s how these myths get started, something works and no one is willing to really test it.