64° wedges have been missing from a few sets, notably the Pings. No reason to worry though, as most of the wedges are sharing the same meter speeds.
Thus it's no problem to mix two or three wedges of different brand or quality (level). Eventually, the longest wedges should be top notch, Cleves, MAX or ATV, while lesser wedges may serve (for a while?) in the shorter range.
Just make sure to have a good and equal spacing and to start short, from 50 or 60 yds.