No, Swapping springs will not get you there...
The shift valves, TV valves, etc.. actually have different land sizes.
Also the governor is different.
It would be very difficult to convert a generic VB to a GN VB.
It would require machining, sleeving, producing the spool valves, etc..
Lots of work,
at about $400 a piece for a GN type VB that's cheap... compared to what the machining would cost.
I am guessing that guys like Bruce and Chris have researched this and developed ways to use a generic VB with great success but they STILL recommend the good VB's.
Probably a reason...
I have a BRF VB, a BQ, and a generic. I disassembled the BQ and compared it in detail to the generic.
I have yet to do the BRF, but will soon, as I will be installing it on my trans, however it should be very similar to the BQ.