As concerns the new E. Gerber 35 mil thick Full-Backs, I'll note that I have many comic books stored with Half-Backs (24 mil) in Archives (4 mil) as well as BCE Thin-X-Tenders (24 mil) in Comic Gards (4 mil) (If I correctly recall, Comic Gards previously had another name circa 1980s and, I imagine, later) and have never experienced any "warping" of comic books.
These comic books are stored in acid-free boxes, E. Gerber and BCE, and are packed just tight enough as are all my comic book boxes, acid-free and regular long and short boxes, that no comic books sags. I also place acid-free boards at each end of every acid-free box and thick regular boards in the regular boxes. Simply stated, all the comic books in a box support each other. Granted, all this may be overkill but it has worked for me since at least 1980.
Lastly, I'll note that I have had some of these comic books graded and CGC has graded all of them 9.8 with white pages. Of course, there are probably some 9.6 and, shudder , 9.4 among them.