Its funny how changing the slightest thing becomes a roadblock sometimes!
Out of interest, how did it hurt your progress? Just because it is difficult, does it mean that it was bad? I have to admit, it was infuriating to get the UWPS 2/4 NPS thing going and it is still lagging behind my DWPS version, but the more I practice it, the easier/smoother my 2WPS has become.
True, but most lines that you are likely to play 3nps for example, will only use UWPS some of the time (especially when you have a definite primary pickslant), the mechanical approach in this instance forces you to use the UWPS all the time - until it is more comfortable. It is generally better (and more fun) to learn and practice ‘real world’ licks, but if you have a specific problem that is a mechanical problem, then a mechanical solution that places laser beam focus on the problem is in my opinion, very useful.