Actually, thinking a bit more, I am not sure that is right. Maybe it's not the number of posts that increases computation but the number of upvotes. And given that a user has about ten upvotes per day (due to voting power decrease), it would seem that the number of upvotes would stay consistent, whether people can vote only on new posts or on new and old.

From the SMT Creation Wizard, I see that there is a parameter called Cashout Window, which I think is the payment period length. As I can see, the maximum value (as per the wizard popup text) is 4294967295 seconds, which by my quick calculation is 136 years. What I am not sure about is whether this is a single-event cashout window, or multiple cashouts can be allowed for SMTs. Maybe @gerbino or @vandeberg can clarify that.

It would be absolutely epic if SMTs can allow for Type II content to become a first-class citizen.