Slide Topper on 2021 Minnie 2529RG?

[Gigman]

I have a 2021 Winnebago 2529RG TT. Thinking of adding a slide topper. I keep the trailer along side my house with a pretty narrow section..roof eaves on one side, fence on the other.

Question is, how far does the slider tube (fully retracted) protrude from the side of the trailer...diameter of the tube?
Is there a difference in diameter between Dometic and Solera...which is smaller? How about quality between the two? Thinking of going with white, to hold down a little on heat...realize it will require more cleaning. Any input is appreciated.