I got my 5500 WideHouse 7 years ago and I have never done anything to “prep” it. Nothing. Ever. It’s still virtually in new condition, windows and all. I’ve never had to seal anything or soak anything. Great hubs, in my experience. The only thing I can think of is perhaps invest in some better/easier anchors. The anchors that came with mine work just fine but it takes too much to get them started (by hand, if you’re using a drill then don’t worry about it). However, 7 years later, I still use the provided anchors and this season I plan on getting an anchor adapter for my drill.
My 5500 is super easy to setup/takedown and the bag is nice and wide too. I’ve never had any issues there. I start with popping the top. Then I hold the seam where the roof meets the walls on the outside (centered above the pull loop) then pop out the sides. I take it down in reverse. Being that the 6500 is slightly taller and wider, doing the sides first may help then push the top up from inside, unless you have real long arms and can reach the center of the roof from the outside.