Re: Modding a yamaha pacifica 012 with Seymour Duncan TB-6 or SH-6.?
Well the Tb-6 will surely better the sound of the guitar. The cavity is the routed area under your pickguard, where the electronics are connected. To minimize hum noises from single coil pickups these have to be shielded against magnetic diruptions from outside. I personally would get a DiMarzio pickup, they even have a Pickup finder and will help you choose on the phone.(Seymour Duncan and DiMarzio are both quality brands nontheless) Going well with the vypyr? Every good quality pickup will go well with a modeling amp. I am using Dimarzio breeds in my Ibanez RG with my Line 6 Spider iv and get great tones, much like Paul Gilbert's tone.
The TB-6 is for Floyd Rose equipped guitars, since you have a standard Tremolo, you have to take the SB-6. There is no difference except the string spacing. I hope that helps.