And it is done! Booked two 2-day hoppers. (With what I spent for just two days, boy do I miss my Flex Pass right now.) Was super easy once finally in. Scrolled down to select number of days, etc. and purchased. Also moved next to reservations page by clicking "learn more," which i agree should've been made clearer.
To add, when checking out, under the type of tickets I was purchasing, there was an additional info link (can't remember exactly what it was called) and it did clearly state there the 13-day expiration for the tickets.
My other window is still at over an hour, but will keep open and offer ID should it start moving.