Thank You Captain!...and YES - like I said, the thumbstrap concept IS excellent to "reach all the notes with ease ".
Even with the thumb in a fix position in TIGHT straps ALL 72 buttons on a really wide range instrument can be reached by ALL 4 fingers when the thumbstrap is working as a pivot for the hand.
One problem with the thumbstrap concept is the poor contact and control - when (!) that is asked for of course! I agree it is not always so, that depends on playing idiom, style of performance and individual habits.
Another problem is the conflicts related to the 4th finger which usually is occupied stabilizing the system "resting" at the "finger rest" which is no *rest* at all since the 4th is cramped and the movements firstly by the 3rd finger are obstructed but the cramped grip inevitably affects the manipulation by all fingers.
The significance of this is evident when comparing with the Anglo/Duet handle concept and of course when using a variant that even more compensates for these weaknesses (not to say defects) of the "english handle concept". This is what I aimed at with the so called "uniform ergonomic handle"
Goran Rahm