My recollection, from when I did it, is that the cavern at the Blue Hole doesn't open up until about 100feet so going to 60 ft misses the key aspect of the dive. Someone will correct me if I have remembered incorrectly.

The Turneffe dives are pretty , obviously not as deep, it takes a bit less time to get there and the trip is a bit cheaper too!

Might be the better option given your understandable caution re depth of dives