there is a form made for Duck questions just like yours. I have never done the type of ducks you are doing but I can tell you, what I'm doing now.. I have call ducks in my incubator right now. I had 13 eggs and 12 of them are showing the veining spider like thing. Yek because I hate spiders.. the 13th egg I got rid of because it was a quitter..
But here's what I do, first I have my temp at 99 to 100 my incubator is not a still one, I have the humidity at 50 to 55, I have to hand turn them, I have them laying flat on the ground because for call ducks I heard this is the best thing. I turn them by hand three times a day and NO it doesn't have to be every 8 hours. I turn mine at 8 in the morning then at 6 in the eveing then again at midnight. I have to do it this way because i work during the day so I'm not home to turn them that second time during the day, If you are GREAT you can set your time up differently. Or use a turner. HA HA HA. Now after I turn them by hand, I take my sponge and mist them. I hear the hatching rate increases if you mist your eggs. So mine get misted 3 times a day.. One time 4 times because I candled them on day 7... Now this is the first time I have hatched out call ducks starting from day one. I'm hoping for the best.
I have hatched out ducks before but i had a good fair start. You see my neighbors duck was sitting on eggs and something was eating them, so they brought me what was left and I was able to hatch them out but it was hard because first I didn't know what day would be lockdown day for them because I didn't know when the mommy had started sitting so I had to guess. Lots of guess games went on with my first batch of duck eggs but I was able to successfully get all the eggs to hatch out. So Good luck with yours...