Usually the damp air rises because it is warmer as it comes from the bees.. It condenses when it gets cold. but yeah, tilted forward lets the moisture drip out the front. some places are worse than others depending on your climate.
I have also started painting the bottom board I think it was LEE that said it makes cleaning them easier.. Many of us grew up in a time that paint was toxic. While I am sure it would still not be good for you to EAT paint, its not as bad as it used to be...
As most others said, the bees will coat the inside of their hive given time.. no matter if you paint it or not, so at worst it is a waste of paint..
I was taught a LONG time ago that the bees NEED a certain amount of condensation in the winter.. it is where they get their water, but having that condensation DRIP on them from above is a VERY bad thing when it is COLD outside.. Painted inner walls will not necessarily promote MORE condensation, but give that condensation nowhere to go.. meaning its not absorbed by the wood... is that a good thing or a bad thing?
I have NOT entered into any argument between the virtues of painted and unpainted inner walls... I have never painted inside, and I know it works, so I have never tried the other way... Finding unbiased scientifically accurate information is difficult, so if I know something works I usually stick to it..
Where you live makes a big difference in certain methodology.. Some methods do not work well in some areas/climates, and I have killed my fair share of bees trying some of those different things.. I have a feeling that if you painted your inner walls that it would not have a dramatic impact on winter survival, and MAY give you a little better longevity on your woodenware...
However... at a great cost of about 5 dollars a box, (making them myself) and having boxes many years old that are still in excellent repair.. I don't paint the inner walls.... I have found that saving that paint to fix the corners I chip the paint off of has made a greater difference in how long the wood lasts.
I know I have probably repeated what many others have said, just wanted to toss my own op opinion into the mix!
Scott