In my opinion its diffently the power valve tech,it's what makes a good blow thru carb work properly. Especially once you start making over 12psi of boost, if you can control when the power valve opens thats most of the battle in tuning a blow thru carb.
Ive modified standard power valves that are adjustable that open under boost and also used what blow thru guys call a crutch setup which introduces regulated air pressure from a air pump ,activated off a hobbs pressure switch into the PV cavity to force the power valve open with good results.
And ive also used something similar to what CSU uses which uses boost pressure in the float bowls and spring tension to control when that power valve opens up fully, that boost pressure is introduced via the vent tubes. The carb I just built for my new setup has one similar to what CSU uses but was designed by SCS PERFORMANCE and can be adjusted to open from 2psi to 10psi there my carb part dealer and great to work with.
Theres more to it then just that but if you can get over that hurdle any other changes are no different then tuning a standard carb.
Just my 2 cents.......