I buy my seals from a seal supplier and get them to change the springs over to o-rings at time of purchase
. If you want a size just flip out the coil spring and measure it. The o-rings do not corrode and weaken the same as a coil spring.
The shaft finish for a shaft that has seals running on it needs to be a ground finish and hard. My pump shaft is chromed by the manufacturer and provides the requisite hardness and wear characteristic. A ss shaft will be quite soft unless you made it from a hardening type ss in the 400 series and heat treated it before finishing to size. Otherwise you will find that the seals will wear a groove in the shaft over time.