There is no "rule" everyone is differnt.
You want a double to fit like a shotgun.
Easy to mount, head errect, solid on the
sholder,and alinged with your eye.
Seek a profossional fitter and may I
advise you to find one who can implement
the changes. If you dont know one ask at
local shotgun clubs. Most shotgun fitters
fit more guns in a year than others will
for many years.

Ken
San Antonio