OK right well all the kit has arrived! I was disappointed to see that the standard McCarty harness only coil taps on the tone pot - should have seen that coming but it limits the options. I like to mix coil tapped neck with the bridge, so bought a couple of tripleshots instead. I had forgot all about these but they are amazing devices - a half hour noodle session can turn into a 3 hour adventure in coil sounds! The number of hours I must have fiddled away with instead of actually recording is shocking.
So I ditched the tone coil tap and wired in the tripleshots and came to realise that the guitar itself isn't muddy at all - which is a bit of a relief. I don't know if the Dragons were to blame or the old wiring. I reckon I could have got away with a Crawler after all, but maybe I'll test one out a little later - tripleshots make pickup swaps fairly quick if you get one for each pickup - so I'll see.
But the guitar has definitely come to life! The Abraxas in the bridge does remind me of an SG in many ways now - it doesn't have the thick chunk of a Les Paul when palm muted so much, but has a very nice open sound. It's certainly different from my Les Paul, which is what I was looking for. Very nice clean tones, especially when mixed with the Emerald. Strumming chords and hearing them decay is very pleasing now - I never realised that the guitar had so much sustain. Also, I play through a Blackstar Dual overdrive pedal, and typically switching to distortion thickens the sound such that ideally a tone tweak is required, but because the Abraxas doesn't have so much of a midrange kick, it takes the distortion very well. It also sounds great when switched to series humbucking, with an interesting shift in tone, with a woody nutty flavour. Sounds very good with great definition. Both coil sounds are very usable too, the poles being weaker, but a reduction in tone and volume remove the more cutting nature and sound very good in driving rhythm. Not as aggressive as a telecaster, but still a usable tone, far better than the Dragons. And when switching back to full humbucking tone again the Abraxas sounds thick and smooth by comparison.
Switching to middle position, I find that mixing the 2 outer coils is a very nice strumming sound. Very acoustic and chimy, encouraging chord and jangly work. I could spend hours flicking the tripleshots between the different coils - I felt that on full humbucking mode, the Emerald probably dominates the sound - at one point I didn't think the toggle switch was working properly until I started splitting coils on the bridge, and of course on a PRS you can't turn the volume down on individual pickups, but splitting the coils on the neck does blend well.
As for the neck pickup, the Emerald is very good. I think I was expecting it to sound much like the original Dragon, as it was said they have a similar spec - but it doesn't really. Very organic and open again. It's a very interesting, resonating sound, encouraging chordwork as much as solos. In some ways it reminded me more of a warmer bridge pickup, probably being the most useable neck pickup I've encountered. I don't know why, I just don't tend to normally migrate to the neck much except for noodling around, but I can see me using this for song writing. Coil splits and going to series makes for a very strummy woody sound, with complex interesting decay, and the full humbucker is into more traditional neck sound, but still maintaining that warm woody overtone - switching back to the bridge does make the Abraxas sound thinner/brighter by comparison, but this is only relative.
As a sidenote, the PRS volume and tone pots in the McCarty harness work really nicely with the pickups, and the tone pot especially creates interesting varieties. Still early days, but now the guitar has opened up and is fun again. So thanks for the advice guys, and glad I didn't go down my usual route as that would have just landed me with something that sounded like what I already had!