Well we do agree on one thing, using your own words, You don't know the internal geometry of the ST Caliper's cavities
These LBS ain't your Moto Guzzi's and again....to Flush and or Bleed the system correctly, you MUST (not shouting, just making a point) follow the procedure in the service manual, which indicates tilting the SMC, or you will just be pushing crap from one circut to the next.
You should take a few hours and read John Heaths articles and photo's on avoiding the pitfalls, and getting air out of the system, as well as his diagrams that show all the routing (in color no less) then maybe you'll understand the ST's system a little better.
Bottom line, Nobody, myself included, should direct anyone on a forum to not follow the correct procedure in the service manual for safety reasons, Period.
I have pointed out "shortcuts" to complete certain services, but those are simply how to reach areas to do the work, as far as following procedures, its always by the book.
No dis-respect directed towards you or your opinion, we will just agree to disagree.