Yea absolutely they stack, I had at least one catalog on each of my characters when I was grinding for Trapezhedron and Platinum Ingots. I would suggest maxing those three or four catalogs out in the weapon upgrades which will give you a much better chance of having things drop from the Adamantortoises.
From my personal experience, I equipped Light with a Connoissuer Catalog which increases the rate of rare drops and Hope had 2 Survivor Catalog which increases the rate of normal drops. Both of them only take like one level to be maxed out so I did that. Turns out that I started getting more Trapezhedron's then Platinum Ingots, currently my ratio is 8 Traps : 5 Ingots which was a little frustrating since my Nirvana was already at like lvl 91 when I started getting all the Traps which simply means I blew like 1.3 million from the beginning of the game plus all those ingots to increase the weapon when I got all the Traps I needed simply from fighting the Adamantoise and winning with 5 star ratings. I'm thinking about putting another Survivor's Catalog on maybe Fang to try and get some Ingots for some money to start upgrading all my weapons.
Bookmarks