If anybody is still interested …
You can’t reduce the recipe too much or it’ll be dry. And more eggs than potatoes (I use loose, not bagged — which are usually larger).
Oomis: you’re right it’s basically done by then except it has to be a big kugel so it takes longer to bake and the overnight idea is that it’s more dense yet soft and moist (think melt in your mouth…) with no visible “strands” of potato.
Good luck and Bon apetit!