You simply do not understand how this market works and you are trying to make it conform to your idea of what it should be or do. It won't.You should also understand that Asian tailors operate at the low end of the market, they best tailors have their origins in the Cantonese region.
Absolutely right, I doubt that they would want to do so simply because of the time taken which could be better spent on 'normal' garments.You will not find any/many tailors in the Tuen Mun area given it is a backwater for visitors. You would need to go to TST or else Central/Admiralty or Wan Chai.
Absolutely correct although I hardly think that is worth it with this lot, all look too small in the small of your back: If that is the way the shop keeper offer them to you to try, go elsewhere as he has no idea of what he is doing.