I use Mylite2s with Fullback Buffer Backing Boards. I tape the flap closed, but I don't seal it all the way across... just a centered piece of tape about an inch long. The book is protected from spills, moisture, dust and insects, yet is not totally airtight so it can still breathe a bit. In my opinion, this is the best storage option for comic books, bar none -- including CGC or PGA slabs. The MyLite2s also display beautifully and can make even slightly worn comic books sparkle.
I recently purchased microchamber paper and insert that between the front and back covers of my more expensive books.
I think acid-free boxes are overkill and don't worry about it as it's not in contact with the books. However, I do change out the boxes when/if they start to yellow.
I keep my comic books on steel industrial shelving with wood shelf surfaces. The dehumidifier is running 24/7 and keeps the room at a steady 53% humidity +/- 2%. The room is about 68 degrees year round.
Any questions? ;-)