IMO and in view of some regrettables losses in the past
tuning the flopper is absolutely essential. However, depending on the shaft/flopper combination this can be tricky (too much vs. too little play of the flopper).
The best "how to" can be found here (two pages from Apnea, in French but with nice explanatory drawings):
Document sans titre
Document sans titre
Cheers,
ulysses
