Well as I think you should be able to decide when to reassign your PSA's to your most hard working Affiliate.
For example in your down line:-
1. Affiliate reaches a EA status assign the affiliate three of your PSA's .(or more depends of how many do you think you can afford to reassign)
2. Affiliate reaches an EA2 status assign the affiliate five of your PSA's.(or more depends of how many do you think you can afford to reassign)
3. Affiliate reaches a Team Leader status assign the affiliate may be 15 or 20 PSA's. (or more depends of how many do you think you can afford to reassign)
Basically the above will be a helping hand from your team in handling the number of affiliates you have.
As they would also have hand on experience on how to handle their down line and eventually make their own down line and have confidence in handling their own.