>"This is the basic flaw with fit systems that have multiple choices..."

in retail, getting "fitted" is part of the salesmanship. my pal and
client invented the fit-kit in the 70s. he'll be the first to tell you
that his motivation was, in part, to raise the bar at the retail level
and to get dealers to get past the "stand over this..." mentality.
a national team skier and cat 1 racer, but a math teacher by trade,
he just couldn't accept that you couldn't find a solution to it all
by using numbers. BUT...the goal was to use the numbers within
the retail store to MATCH a buyer to a pre-existing bicycle in the
dealer's inventory, NOT to design a bicycle around or to tweak
a position. the only way to do that is to
1)ride lots yourself
2) to build so many bicycles so many ways that you develop the
skills and confidence to do it from experience.