A few years ago there was a blind national survey of peafowl breeders where all results were anonymous, no one could know who was participating and only those in the study were given the end results. All factors were calculated into the study, location, male-to-female ratios, age, cracked and or broken eggs, clean, washed, dirty, broken off the roost, and much more. One of our members here who does not post anymore was involved and told me much of what was released. Large producers were very happy if they had a 40% hatch rate. The only time I could ever say I had a 100% hatch rate is when I only counted the birds that hatched. To be truthful to oneself you must count every egg even the ones that you know better than to set. Your best results will be with a broody hen, no artificial incubation is going to outdo nature but even then you will run into problems with other birds in the pen disrupting the process. You will hatch just as many chicks with a 1:3 ratio as you will with a 1:4 or 5 ratio. Social harmony is a big factor in that as well. The largest breeder in Tejas, maybe in the US told me it is not the number of eggs you gather to set or even the hatch rate that is important but the number of chicks that survive to sell that is important.
There are so many factors to consider none of us get it right or peas would be just as cheap as a $2. chicken.
To answer your hatcher question; I have three hatchers, Brinsea 380, Lehy 416 redwood, and a Brinsea hatcher. The breeders that honestly told you they have a 40% hatch rate in the GQF are doing well with them but are spending a lot of time turning eggs and watching the humidity. That is extra time I don't want to invest when the auto humidity control will allow you to do other things like be gone for a day or two without worrying too much.