CS 23.155 Elevator control force in
manoeuvres
(a) The elevator control force needed to
achieve the positive limit manoeuvring load
factor may not be less than –
(1) For wheel controls, W/10N (where
W is the maximum weight in kg) (W/100 lbf
(where W is the maximum weight in lb)) or
89 N (20 lbf), whichever is greater, except that
it need not be greater than 222 N (50 lbf); or
(2) For stick controls, W/14N (where
W is the maximum weight in kg) (W/140 lbf
(where W is the maximum weight in lb)) or
66∙8 N (15 lbf), whichever is greater, except
that it need not be greater than 156 N (35 lbf).
I think that this links into 23.337 which also makes N1 a function of MTOW, where:
N1 = 2.1 + (24,000 lb / W + 10,000 lb)
[with a maximum of 3.8]
So given that a heavier aeroplane has lower g limits, you therefore want a steeper stick force per g gradient to ensure a minimum high stick force to pull the wings off.
Section S, a wonderfully simplified code used for microlights in the UK simply has a value of 7daN at N1, which is a lot easier to work with.
Good question!
Sidetracking a little, I personally believe that whilst this is important, more important to safety is the concept of PFTS - or "Pull Force to Stall", which exists in a sort of oblique way in part 25, and an even more oblique way in part 22, but is not anywhere in part 23 or VLA.
G