This is pretty much my experience of the 509 Pups and range of tones you can get from one. I must admit, I thought the Humbuckers were 'hotter' than the figures suggest, but not 'hot'. Until I bought my Custom 24 Floyd, I had no pickups over 10k and was a bit surprised the 85/15's are a bit hotter according to the numbers.
I don't find the guitar too bright at all. I admit mine is a regular 'core' with Mahogany body and neck with a Rosewood board. I know they have done some WL runs with Swamp Ash bodies and Maple necks which would make it more like a 'Strat' build (with a set neck) and change its characteristics. I also tweak my settings when switching between guitars going from a Cu24 Floyd to a HBii with Piezo will change how an amp sounds and reacts. If I have an Amp set up for a 'Dark' guitar, then a normal guitar would sound 'brighter' with the same settings.
In my opinion, PRS do not currently make another guitar like the 509. The closest is probably the Studio (or maybe Fiore?), but that's still quite different. If you are looking at the 509 because of the way the Pups and Electronics are arranged and the versatility that offers, then its worth at least trying one yourself, make up your own mind. The sound of the Pups is 'subjective' and even if everyone tells you they are superb, you may feel differently (or vice versa). It could well be the 'perfect' guitar for you and your requirements - so 'try one yourself'.
This is my 2017 509 - bought new in 2017 and still a regularly played guitar in my collection. I can recommend at least trying one - great guitars!!
