In article , Greg Esres
wrote:

BUT, there are 2 things (at least) which contribute to the setting
of Va in the first place.

Neither one of the things you mentioned is given in Part 23 as a
requirement for Va. Part 23 uses the speed solely to provide the
design requirements of the elevators, ailerons, and rudder.

Since the forces on these control surfaces will not vary with weight,
you certainly can't scale it up.

G-forces are directly related to weight. Since the size of the control
surface is directly related to the forces exerted on it, control
surfaces are dependent on weight.