My "way" of looking.
Edge Pro has the metal inserts on each saddle. Saddles look flat. Find these on the higher end models since '03
Edge Pro II and III do not have the inserts. Saddles also look flat. Find these on the Korean RGs
Original Edge doesn't have the metal inserts but has a higher profile, due to the saddles looking a bit bulkier. Find these on older (pre 03, I guess) middle/high end RG/JS etc guitars
Lo Pro Edge has a lower profile because the fine tuners are located right after the saddles (JEM, some LTDs, JCs I think pre 03 as well)
Lo TRS II has a screwin bar, and has smaller posts. The "wings" are shaped a bit more diagonal than the others. The trem itself seems thin.