Thanks everyone for your responses!
Between my 594 and Silver Sky compared to my 2008 DGT, the two newer guitars seem to play more "buttery" than my DGT. The DGT still plays better than all my other guitars, but the 594/Sky are on a whole new level of playability. Maybe for that reason alone I should be checking out the newer McCartys with 58/15 pickups. I used to have trouble getting along with the old wide/fat necks too, but I wonder if the earlier examples from 1994/1995 have the same profile that gave me trouble. It would be lovely if I could try all 3 versions back-to-back but that opportunity has never presented itself.
I can't argue with your impression of the playability of your newer guitars comparatively to your older DGT. That being said, Paul Reed Smith would say that the guitars he is (well his company is) building better guitars today than ever before. As for your experience, it maybe that the frets are newer and that is contributing to the difference - maybe not.
Before CNC, Bodies were carved on a 'copy router'. - a jig essentially that has rod on one side with a carved top and on the other side, a blank with the router. Someone would trace the rod over the carved top and the router would copy that movement and thus carve a top - which like CNC tops today, still have to be sanded by hand to remove the tool marks. I am not sure how the old necks were carved - possibly by hand but I do believe there was a greater variation. CNC means that they can 'pre-carve' the neck down to same size, following an exact pattern so every neck that comes out, is pretty much exactly the same shape. Like bodies that come out of the CNC, these necks still have to be sanded by hand to remove tool marks and get them smooth for finishing.
What this means though is a lot more consistency with each neck. They may not be exactly the same but only vary by hundredths of a mm (I am only saying this as an illustration of the tiny differences that may be present but don't have an accurate figure of the tolerances - it could be tenths or even thousandths if a mm but the point is, its far more consistent. What that means to a customer like yourself, especially if you are very sensitive to neck shape - their thickness and width, if you try a Pattern Regular and it feels right, then you know all Pattern Regular necks will be the same.
The DGT has its own neck carve too (I believe) and obviously the 594 has the Pattern Vintage carve but I don't know about the Silver Sky myself. Apart from any Signature carves that are unique to that model, the Pattern Vintage is the chunkiest neck with the 'widest' nut. I say Widest but its the same width as the Pattern and Pattern Thin. Pattern Regular is the narrowest - according to PRS - but its 1/32nd of an inch narrower - or 0.8mm if you are talking Metric. As someone with all the 'Pattern' neck carves, to me they are all similar enough that none pose a problem - the pattern vintage is the most recognisable because it feels the most 'worn in' but in a blind test, I don't know that I could say with any certainty what neck I was holding. When swapping, I have to spend more time getting used to the switches and knobs but apart from the Vintage neck, the others may as well be the same.
I am not you though and you may well be far more sensitive to those minor differences. For many years, I just played my Acoustic which has a small narrow neck with 'low' action - at least compared to a LOT of acoustics - it was that neck and action that made me buy after a 2year search. However, compared to that, I find PRS guitars to be 'small and that includes the necks. To reiterate, that's coming from an Acoustic that was relatively small for an acoustic and a bit bigger than my Epiphone LP so I am not the most sensitive when it comes to neck thickness or width - as long as its not too thin or narrow, I am ok
The best I can suggest is that you do a bit of testing out yourself. If you can get to a PRS dealer, try a Custom 24 with Pattern Thin as that's the most different from Pattern Vintage. If you are OK with that, then I see no reason why Pattern and Pattern Regular would be an issue either. If you can try a Custom 22 with Pattern Regular too, you should have a clear indication as to what PRS necks work for you. As for Pick-ups, again that's something you really ought to try. Obviously the Custom 22/24 come with 85/15's and you know what 58/15 LT's offer too. As for putting them in a DGT, again that's something you would need to try as they can sound different i a different guitar. At the end of the day, that aspect alone (sounding different in different guitars) makes me feel uncomfortable making any recommendations and to be honest, that can be trial and error. I have friends that loved a set of PU's so took them out of an old guitar to put in a new guitar and hated them - so put them back in the old guitar.
Anyway, I hope you enjoy the hunt, enjoy the experience and come to a decision that best suits you...