I have a trac II I use occasionally for head shaving, but find the Atra with the pivoting head works better on the angles on the old noggin.
Nice rundown! Yes any razor cartridge with two blades or more uses the Hysteresis effect. My first bought razor was the Gillette Sensor and I still admire it and love it for nostalgia reasons. The Mach 3 never quite agreed with my face and is the only razor to really cut me bad (I still collect vintage models though). Long use of the Fusion results in ingrown hair for me.
Yeah, the Mach 3 and the Fusion both continued the lift-and-cut system marketing. I remember the commercials featuring animated demonstrations of how the cartridges work. Gillette simply doubled and then quintupled down on the multi-blade system. Now that safety razoes have made a comeback and cartridge sales are down because of over-pricing, the company is starting to get back into producing safeties in order to catch up. Time will tell if Gillette succeeds.
Gillette Trac II cartridges are getting very cheap online, approaching the cost benefits from double-edge blades. https://www.amazon.com/dp/B001F51R6K/?tag=thshde-20 Double-edge blades are 100% recyclable, however, which appears to now be the driving force behind cart shavers switching to safety razors. Maybe not among the forum hobbyists, but overall from what I have seen. Who woulda thunk?
Put them in a blade bank and, when the blade bank is full, chuck it in the recycle bin. The blade bank is metal, so it can be recycled, too. I get mine from Em's Place. They hold over 2 years of blades each despite their small size, and only cost $2.