DIfferent NAXO 2-4s for Kans and SBLs?

Certainly the SNAXO 2-4 was equally applicable to the Kans, Tukans, Saras, SBL, IBL, Credo, Keilidh, Magik 140, and possible an odd Audiovector model, all using the same 2.7k crossover point and 18 db/octave slopes. And it works surprisingly well seeing that you would never dream of putting say the passive Audiovector crossover into the Kans and expect them to be reversely compatible. Certainly a dedicated Snaxo per speaker would have been optimal, tailored to required transfer functions-but this would have been prohibitively expensive and resulted in at least a half a dozen (or more) different versions of the 2/4.  

I remember when I changed from Active Linn Saras to Active SBLs, Derek Whittington tweaked a couple of potentiometers in my NAXO (bought long before the SNAXO came on the scene!)

Yup, the same, but with different level settings.  

Thanks for the education.

Are there specific settings for the pots that are deemed "official"?

The tweeking of the potentiometers inside the Naim crossovers was purely about relative levels between bass, mid and high, (in the case of the three ways), and just bass+mid and highs with the two ways. Given the broad frequency ranges covered it was of limited use, but still useful if used with a light touch.

Also given that back in the day virtually all the active speakers from Linn and Naim used the same basic family of drivers, (Scanspeak and Kef, with massaging for sure),  the crossover points were pretty universal.

I  did always wonder why there weren't more cards developed for different cross over frequencies, as the beauty of the early crossovers was you could just drop cards in easily. The NAXO could even be changed from a two way to three way. The cards weren't complex or appearing to be particularly hard to engineer. The concept is akin to the early phono boards. Why not just swap them as your system changed, and certainly fits with the great longevity of Naim product.

I know active is a niche enterprise, but other guys are doing it with versatile, modular systems. Given how robust a Naim chassis is, the already great range of power supplies and well established cable logic, I still can't see why a range of crossover boxes, say 2-4 and 3-6 with a couple of performance levels and with a range of crossver cards isn't viable. Naim owners are in it for the long haul, and love collecting black boxes.