Probably Fundies for the sheer amount of concentrated work, challenging it in doubles, and by dive #49. Followed by Tech pass 20 dives later. It really set a solid foundation for everything else after.
OWSI as well, as it was the culmination of a lot of work, and pushing in areas other than scuba skills.
OWSI as well, as it was the culmination of a lot of work, and pushing in areas other than scuba skills.