I started misting the eggs after I read that it can improve Muscovy egg hatch rates, and use a lot of the info from this thread: https://www.backyardchickens.com/a/incubating-and-hatching-muscovy-eggs. Basically, you mist the eggs with warm water from a spray bottle, in conjunction with cooling (taking the top of the incubator off for a specific period of time, varies depending on how long the eggs have been incubating). While my incubator has an autoturner and cooling function, I get the best results hand-turning (3xday) and manually cooling/misting. I've been able to watch my Muscovy broodies dampen and cool their eggs in their nests this summer - the misting/cooling method mimics natural incubation. It does temporarily boost humidity in the incubator, but the autocooling feature does the same thing and it doesn't seem to have an adverse impact on hatch rate. It may also seem counterintuitive to take the top of the incubator off during cooling, but the broody will leave her eggs for 30+ minutes at times, so it's actually perfectly fine to do it briefly to cool the eggs (but you have to learn to ignore the little voice in your head saying "don't open the incubator!"
Muscovies are great, and addictive - I hatched a couple of sets and let a couple of broodies hatch a few this year and it's like a "ducksplosion" happened! LOL They're excellent foragers, smart, and have a lot of personality. I clip one wing on mine because they can fly really well and like to roost up high. They'd be happy as clams in your climate, too and probably eat every slug in sight!
Hens go broody when you don’t want them to… and won’t go broody when you do. 
