Make your design 2 colours - in this example the stars, stripes, rank, logos, and words would be white, and everything else black. I think you’ll find pine to be far lighter than you’re looking for - though you can always stain it any colour you want.
Once you have an idea for your design, grab some simple MDF or plywood and run any complicated sections at full size (just the section) and the whole thing at a very small size - so you can see how the design will look (making sure you haven’t done anything the wrong colour, or way too skinny, etc). Then run it on a nice piece of wood to get your final 