Platinum Patch / Parbond - questions on use

[PatLee]

There are a few places on my AirstreamI want to preventatively seal. One is at top edge of one window, another at the top edge of the stove vent; and one 6" long seam on roof (in white area). I have both aluminum-colored Parbond and white-colored Platinum Patch sealants. Photo attached.
The Parbond tube says not to use it for filling any seam wider than 1/8'.
Platinum Patch's website says: "DAP® Platinum Patch should not be used . . . as a caulk, sealant or joint filler over cracks & joints where expansion & contraction may occur." My questions are: -
1) Do any of these seams I'm going to seal expand or contract?
2) Is the Parbond just for application on the vertical/horizontal seams on the aluminum sides of the Airstream?
3) Is the Platinum Patch to be used on the white roof?

Thanks for your insights.