Personally couldn't back a Hong Kong horse over 2 miles - they are a 1200m-2000m racing jurisdiction for mine - the locals generally get lapped by whatever the Europeans send over in the Vase and thats only 2400m.
I couldnt back a Hong Kong horse outside of HK with any confidence full stop. They do have some good horses but generally speaking the class of horse that races there is quite poor in my opinion