The "gray sail" schemes weren't experimental, they were just evolutions to past patterns. During the war, Submarines were sometimes Measure 9 (all black), but more often they were in a submarine based version of Measure 32 (dazzle) that was either pattern 3SS or 9SS. The big take away is that these two schemes featured black decks, but lighter gray sails so that the subs could operate on the surface and be less conspicuous. The only difference between the two schemes was the gray that was used; one was a light gray and the other was a dark gray.
The 1953 Camouflage manual continued this - the schemes that were settled upon were the same and the only difference was the gray that was used (light, medium, and dark). "SS 7" used #7 "Navy" Gray, "SS-17" used #17 "Ocean" Gray, etc. Below is a snipped from the 1963 manual:
There are only three basic concealment painting measures for surface ships and four for submarines. With the exception of the LC measure for surface ships—which is a unique application of paints designed primarily to blend with foliage patterns along shorelines—all paint measures are variations of gray shades from dark to light. These measures are designated by a number ("7," "11," "17," or "27") which equals the percent of light-reflectance of the gray paint applied to the large vertical surfaces—the sides—of the vessel under that measure. This degree of reflectance determines the darkness or lightness of a measure; thus the larger the percent of reflectance, the lighter the measure.
Following is a list of the authorized concealment painting measures:
Surface Ships
US17 (Basic shade of "Ocean Gray" applied to sides)
US27 (Basic shade of "Haze Gray" applied to sides)
LC (Foliage pattern of mottled greens, brown, and black applied overall)
Submarines
SS7 (Basic shade of "Navy Gray" applied to vertical surfaces)
SS11 (Basic shade of "Outside Gray" applied to vertical surfaces)
SS17 (Basic shade of "Ocean Gray" applied to vertical surfaces)
SS27 (Basic shade of "Haze Gray" applied to vertical surfaces)
The vertical surfaces by this time were just the sail - the turtle back did not count. Now, these weren't experimental schemes, but they weren't for every sub. Boomers shouldn't surface on patrols, so there's no need to have the gray sail, and the all-black sail becomes more appealing because it's better camouflage in the deep.
Essentially, nuclear power and ELINT aircraft killed the gray sails.