I have a dedicated 220, but thats all. I did have issues with consistent results the first couple months, but I cant say for sure it was power related. I suspect there was some burn in time needed on the elements, but no way to quantify that. When I pick up another one, Ill be running back to back cycles and high temp purge cycles right away before it goes into production, just to get things broke in.
Temptabs from Orton ceramics are a must. I use a 650 and a 700; measure with a good micrometer and average the two. My oven runs just a bit cold. Every Zr Ive tried looks better in my eyes slightly over cooked.
Have you decided what material(s) youre going to use?