I have been reading about how to make Piranha solution and I keep coming across this statement,  “Add the acid to the peroxide, although some authorities disagree”   Why would authorities not agree that adding acid to water instead of water to acid is best?

I have seen some say add acid to peroxide for initial solution, but when refreshing, add aliquots of hydrogen peroxide to Piranha mixture.  Is that ok?

We recently had an incident when Piranha came in contact with ferric chloride and instantly reacted

violently Was this due to the metal, the fact that both are oxidizers, both, or something else?

I have read that neoprene gloves should always be worn.  True?

What type of glass is appropriate for containment?