Jake, these gears worked fairly well on old commuter bikes, when I repaired them they had generally run out of adjustment, and frequently full of rusty water, but not under much stress from the pedals.
Sporting riders in the 1950's always used gears in direct drive. Firstly able to choose ratios, secondly less liable to collapse when pushing hard.
The SA is under more stress the lower the gear.
Obviously to climb a hill at the same speed the stresses would be about the same, its when you try to accelerate that it's worse.
Keith