OK, thanks for your post. I took my air assembly out (pictured below) and removed the u-cup seal Part number: 036-01-018 looking this up on the Fox website:
http://service.foxracingshox.com/consum ... 8_RevA.pdf
shows the ID as 22.45 mm. Now, according to this page:
http://service.foxracingshox.com/consum ... tslist.htm
my Floats (dated stamped 06 / 2002 so probably a 2003 model) should have a 036-01-010 u-cup seal:
http://service.foxracingshox.com/consum ... 0_revA.pdf
Which has an ID of 22.91 - 0.5mm larger just as you said! The seal ODs are listed, my current 036-01-018 has an OD of 27.81mm whereas the 036-01-010 I need has an OD of 28.27mm.
I tried the '08 float top-cap assembly in the 2002-3 stanchions and they were a little free on the threads but bedded down well against the o-ring.
"Sometimes glass glitters more than diamonds because it has more to prove" Terry Pratchett