Flybobby, the best way is to visit your next colour-shop and decide by the colour-charts as there is a Registration No. on that colours (RAL- No.). If you have ever seen the origin, some days after painting the colour already changes- depending on salt and ultraviolet light. Though, as you have a wooden deck you need to prime the deck anyway. Another argument for visiting a paint shop as they may tell you which paint to use.
Hope this was out of any help,
Jörg