I used 50 hfe Russian MN39B PNP germs, because I do not have any 2N2613 (as used in the original). So just socket the germs and experiment with different ones. In other builts I have used combinations of different types, because sometimes that sounds better. Even if the schematic specifies only one type.
This circuit is based on the Maestro FZ-1, so selecting transistors should follow similar logic
In fact, I recently got a Maestro FZ-1A, and the transistors are 2N2614 (it sounds really good too). So searching for transistor info on the FZ-1 and FZ-1A should be helpful with this less documented circuit