I am in Hong Kong now.
I've frequented the famous Kwong Wah Street many times in the past and this trip.
Harmony model's staff is extremely rude. Don't go there. As you can see I'm not the only one who says they are rude. They are also intimidating if you ask them questions and you are unsure (aren't staff suppose to help?)
I end up buying about USD one grand with Action Hobbies. I've seen Andy the owner rude to other local Hong Kong people in the past as well if they just keep looking and ask unreasonable requests but he wasn't rude to me. You have to understand Hong Kong is just crazy full of people lol! His shops is packed with people most of time in afternoon and evenings even during week days!