The Commonwealth Catalogue which was published by Murray Payne lists three shades for the Hong Kong $2 (second set of colors). They are listed below with my example of what I think is the stamp they described:

$2 Violet and Red on Substitute Paper - 1946

$2 Purple-Violet and Red on Chalk Paper - 1947

$2 Violet and Red on Chalk Paper - no date mentioned.
I am pretty sure there are more printings.
It is pretty difficult to sort King George VI stamps using used copies because they are not in the same condition as when they were issued. I see a lot of change in your stamps that do not appear on unused issues.
Try at least sorting for the substitute and chalk paper issues. You can use a piece of silver and lightly draw it across the bottom margin to test. Chalk paper will yield a pencil like line. If you don't want to mark the stamps, try lightly rubbing your finger across the surface. Chalk paper is smoother and will feel slick compared to the substitute paper which will tend to drag a little bit.
I have a King George VI Collectors Society Study Paper on the Hong Kong set, but can't seem to locate it at the moment. If I can find it, I will let you know how many printings they show.