According to an informative source who worked on these motors in a GM dealership, what you performed was what they used to, do to the letter.
First was to adjust the rear main bearing itself because that would stem the flow soemwhat. By the procedure in the manual, if you removed one shim from each side and the motor was not too tight, this adjustment is just fine and needed.
For the seal, it was standard procedure to replace the bottom only because you can run into real difficulty trying to get the old one out of the top, with the crankshaft in place.
Congratualtions on your success. as far as whether it will start leaking again, there is no reason to worry about that. I would just keep an eye on it just like you would the rest of the motor.
