I still haven't found out what set the maximum folded span at 27' 6" in the early 1950s. Before then, folded spans for the jets varied somewhat but were almost always less than 27 feet. Exceptions were the big strategic bombers (the AJ, A2J, A3D, and A3J) as well as the Douglas F5D, which had a folded span of 28' 5". I had thought that it might have been set by a pinch point in the middle bay of the Essex-class carrier hangar deck:
The Navy's contractors paid close attention to the size constraints. As previously noted, the McDonnell XF3H-1 was 59' 4" long, which maximized its fineness ratio but required it to be carefully positioned at an angle on the forward elevator of the Essex-class carrier. The Navy did not like that.
As an indication of the attention that the contractors paid to spotting in predesign, here are two pages from Vought's 1952 proposal for what became the F8U Crusader. The V-383, which was powered by the Pratt & Whitney J57, has a folded span of only 22' 6", but was more than 54 feet long, so only 25 could be accommodated on the forward or aft 200 feet of an Essex-class carrier compared to 27 of the slightly smaller and lighter V-384s, which was powered by the Wright J65. Note that two V-383s can be positioned on the forward elevator without being angled.