I put a Perception saddle in a Mad River ME I bought from John Berry in 1983, which motivated him to buy one to install in his teaching fleet of ME's.
Nolan Whitesell put them as standard equipment in his canoes, including adjustable toe toe blocks drilled through the foam block that had to be placed under the saddle and glued to the canoe bottom. I bought my Piranha from Nolan after we paddled the Ocoee and Section IV of the Chatooga with him in 1986. I still have it. Here's Nolan in later years:
Our CT AMC club installed a Perception saddle in our rental Blue Hole Sunburst II, which became our most popular rental canoe. The saddle broke loose from the glued bottom on me on the Rapid River in Maine when I was doing a strong low brace, causing me to lose balance and swim right above Smooth Ledge, where legendary squirt boater Jim Snyder happened to be teaching Mystery Move classes. Embarrassing.
One of our club couples put three Perception saddles in an ME for both tandem and solo paddling, but decided the canoe was too hot for them after all that work. It was a heavy sucker.
There were blocky foam saddles wedged under two thwarts long before the Perception saddle, which was intended to improve upon their ergonomics and do away with thigh straps. I liked the Perception saddle a lot, except for its weight. It fit me well. The storage wasn't all that useful, as the hatch was very hard to twist open, especially with cold and wet hands. The high rear sitting surface was usable if you had good balance, a wide canoe like the Piranha, or both.
Bob Foote came out with his own version of a plastic saddle a couple of years later, called the Grand Canyon saddle. It used thigh straps and had depressions for two bottles and an ammo box in front, and bungee cords to hold a rope bag in back. My club had one of those in a canoe, too, and I know planc has or had one in his collection.
Later, I preferred custom-fitted, hand-carved foam pedestals with hip blocks secured under one rear thwart, offered by Tom Foster and John Kazimierczyk and perhaps others.