Do you mean what pickup I'm using, or how I'm deciding which pickup to use?
The pickups are factory standard for an American Ultra. THey say noiseless on them. As for deciding which pickup... I'm not sure. Still experimenting really. I've had the PRS for longer - I started with a custom 24 as my 'main guitar' as it's so versatile (and it feels very good to play!). But then I wanted some other tone options, so I added the strat and also a PRS hollowbody 2. I'm still playing about with those two, finding the best way to use them.