We have mild, wet winters here. 80 days rain of 120 for a winter season- rare to get snow (but we saw it a few times and it stayed around). We have no small hive beetle. We have about a dozen days a year that it gets to be above 90f
The hives that I have built SBB for all made it through another winter, all of my losses were from the solid boards. Some at the bee club say it is too much ventilation and the new thing last year was placing a board so that only the center was out to carry moisture through a modified, divided quilt board (open center for broken sugar candy) to get air flow through the center. I have just recently taken a hole saw to the bottom of the solid, divided, bottom boards and screened them to do a hybrid without spending a bunch of time or money.