I think you are very correct that in most backyard hatches, we simply dont have the proper tools to control our temps and humidity levels to the exacting levels needed to prove or disprove any studies that are found on the internet. Still, these type studies do have merit and gives one pause to think what if. As you mentioned, with the current affordable incubators, any change in temp adjustments would mean babysitting the incubator for hours just to be sure we didnt overdo our corrections. I am hopeing to change that. Take a look at this thread,
https://www.backyardchickens.com/forum/viewtopic.php?id=248824.
I dont have this controller in hand yet as we are still waiting on the software engineer to finish writing the software, and then it still has to be tested. While the software is programmable in this controller, its not set up to to raise or lower temps beyond the the initial setting, but is supposed to be accurate to 6/1000 of a degree, and will read temps and humidity in 1/10 increments. Until reading this thread, I thought such accuratecy was overkill. To make this same controller programmable to change desired setting during the incubation period should only take a software tweak, provided the microchip we are using has sufficient memory. If this is the case, you could be able to set the desired temps for incubation periods of 10-12-14 days, or whatever and then have the controller automaticly change to another desired temp for the remaining number of days.
After reading this thread, and the thread by Speckelhen about her egg-o-meter. I am considering also adding a seperate thermostat whereas the sensor would be mounted in a plastic egg for placement in the incubator trays. This would be a inexpensive electronic thermostat and would act as a backup to prevent the actual egg temps from overshooting the desired temperature inside the eggs. We already have this type of thermostat on hand and would only mean incorporating a digital readout so you would know what the actual temperature is. To maintain a high degree of accuratcy, it would also require a slightly more expensive sensor which would probably double the cost of the eggometer thermostat. The sensor in our digital programmable controller cost $35 buying in bulk from the manufacturer, where as the sensors found in your accurite type thermometers only cost a few pennies. Both sensors do the same thing, but being accurate cost$$
I am going to talk to my engineer in Thialand to see what changes can be made without having to completely redesign the controller. Since the first prototype is already built and waiting on software, we probably wont change anything until after testing.