I'm trying to catalog some Cook Island issues that have sailing ships on them. I've a Cook Island-NIUE-1/2 penny, a Cook Island 1/2 penny, and a Cook Island Aitutaki 1/2 penny. Many of the issues in the 1920's to 32 look alike. Now I find another issue in 1944-46 for yet another A12 listing. Need help putting the correct cat. # with the correct stamp issues.The A-4 is a small sailing ship, the A-12 shows a much larger ship and the A-5 is ships at a waterfront.