Not sure if you have Academy stores in your area, but they sell some numbers that have some color to them that you may be able to get a better match for your boat colors. They are also written a little like the paint designs on our boat and are cheap.
I attached a picture of them on my boat. They tend to have a transition in the color, so mine go from purple at top to green at bottom, and purple and green are both the colors of my boat, so even if they aren't EXACTLY the same shade, they look better than big square black letters.