I don't use lubricants, because I find the tuning on PRS guitars very stable. But if you find you need them, heck, you're not going to kill the guitar if you decide to use them.
The finish on the guitar isn't nitro, it's V12, which is a proprietary finish developed by PRS to be a lot like nitro. The Private Stock guitars are available in nitro, but V12 doesn't require nitro-safe polishes, and you don't have to worry about the finish checking as with nitro.
I'm of the belief that the less abrasive polishing you do to a guitar, the longer the finish will last. So mainly I just use a damp microfiber cloth, and follow that up with a clean, dry microfiber cloth. I recommend the thick, fluffy ones available from Griot's garage, as the long fibers absorb dirt and moisture very well, and won't mess with the finish (even cotton will abrade a finish - find a clear CD case and rub it hard with cotton, then try it with a good microfiber, you'll see a difference).
https://www.griotsgarage.com/produc...+set+of+3.do?sortby=ourPicks&refType=&from=fn
However, minor swirl marks, etc., can be buffed out to a high shine with Virtuoso polish, which is a very mild abrasive polish, and for heavier needs the Meguiar's New Car Glaze is very effective stuff - and they have polishes with progressively more abrasive for very heavy needs, but I haven't ever needed anything more.
To simply give the guitar a nice shine, the PRS Cleaner is really good. I spray a small amount on a microfiber cloth, and it gives the guitar a nice shine. Maybe I'll use it when I change strings, but honestly, the finish stays so nice looking with just the usual damp cloth cleaning, that it isn't truly necessary.
I personally found the PRS polish a little too abrasive for my needs when I tried it years ago, it seemed to be the typical guitar polish that so many companies put their label on, but that may have changed.