I have 3 x 50 cm (tad under 20" because they are metric) rides. All have the pyramid stamps.
[img]http://www.robscott.net/cymbals/wp-content/uploads/2010/11/ufip6.jpg[/img]
Two also have the round "Made in Italy" pressed in underneath, the third just has the pyramid stamp itself. These oldies are all light. 1675g, 1725g and 1836g. The only rides UFiP make in that range today are the Experience Collector series rides.
I also have a pair of Class Brilliant 14" hats which are made from two 14" crashes and similarly light compared to UFiP hats. These date from when Billiant wasn't yet a separate series so they have the Experience logo. Weights are 750g and 805g. Your heavy hats will be rather different in weights from my pair!