I have seen P100 used as a reducer in LEs and LSs, and then a ferrule with an OD of .240 takes the actual load. Whether the ferrule is solid or hollow depends on the application. Not sure how much weight a tubular ferrule will save, though.
On my Talon Std, I have successfully substituted the P100 used in the LE for P1X (http://jestofevekites.com/techtalon_std.htm
). Mostly because I had a scrap piece of P1X around, and it nicely matched the look of the P2X ULE that Mark had used on my kite in place of P200. I have never felt a difference in performance, though, and I doubt there would be anything measurable.