how much ventaltion

I just put in a screen bottom board from Kelly.
Should I take the mite board out completely or just pull it out a little? Its been rainy and hot with high humidity. More rain today poo

I have a vent on the cover above brood box as an entrance.

Take it out. Replace it when nitetime lows get below 50. It's hard to overventilate a colony with just a SBB. Send some of that rain my way and I'll give you some dessicated air to help the nectar cure :D.

I use screened bottoms "open" all the time. So far, I do not think there is such a thing as too much ventilation. I use vented tops also. If the bees need more ventilation, they just fan. If they need less ventilation they just fill in the top space. I do not limit them, they adjust to how much they need. I am in a high humidity area also.

As a recovering WI resident, I'd say check with some local beeks on overwintering with an open BB. Once they hit -35 F, I'd guess the girls would thank you for the floor :).

I run my SBB wide open all year. This time of year, I've got entrance holes drilled in my deeps that I open up too. Come winter time, I close up the bottom entrance, and let them use the hole on the upper deep for an entrance. I've also got slatted racks - jury is out on them yet though.

I really don't think there is a thing as too much ventilation. The bees can keep themselves warm/cool - it's the humidity that is the problem.