For staining the basswood parts, I used Minwax products as shown below.     I first applied the Minwax Pre-Stain Wood Conditioner to the basswood.  Then I mixed one part of Minwax Golden Oak Stain to three parts of Minwax Natural Stain and applied this to the basswood parts.  This darkened the wood very slightly and this was the effect that I wanted.     As you could see, the color of the frames were darkened very slightly.   Here is the keel stained.