My pin setup has been:
Rindo: Triangle button (of course) with the fire sword pin, it's an absolute beast of a pin when I first got it, Yukimitsu
Fret: Square button ice bubble pin. Reloads fast.
Nagi: R1 button light bomb pin, and I equip the helpful smartphone accessory that changes the R1-Charge requirement to a tap for instant attacks, real life saver
4th Party Member
Beat
: L2 Hold Time wind pin, it blows the enemies away and rapidly increases my groove to 300% when I pair it with the other members attacks just right
5th Party Member
Shoka
: Pin Grinder for pins I want to see the evolution of, or same as above which basically ensures me getting 300% every battle when I drop the beat just right; the boost grinder pin is helpful for this
That's for set 1. For set 2, I switch it up a bit:
Fret: Bomb pin. 1 time use that has this huge bomb which gives out massive damage IF I plant at the right spot at the right time
Nagi: Ice Frost chain pin, holds enemies in place AND makes them take damage while they're stuck
4th Party Member
Beat
: Darkness Sword Pin, just because its so fun to use. Otherwise it's a healing pin
5th Party Member
Shoka
: Vortex Pin, to suck up all the enemies onscreen and keep them in one place for the bomb that's about to go off on them
http://i.imgur.com/0UFI0T9.jpg