This is just a matter of curiosity. What is the difference between a Marble 1 and a Marble 2? They seem to do the same thing to me.
By Marble, you mean the MRBL items? #1 reduces encounters, #2 gives you a single perfect hit (Critical.)
#3 reduces encounters Maba.
From what I can tell between #1 and #2 they seem to be the same. Weird.