After several weeks of business trips and other distractions, I was able to get back to work yesterday. I found a supply of pine for bass bars - enough for at least a dozen instruments. I don't know its provenience or age, but the wood is clean and tight-grained, perfect for this application.
I used the Luthier's Friend thickness sander to dimension the bar in width and height. Getting an approximate fit contour was fairly straightforward. However, getting an exact fit is more challenging. I know I have a supply of carbon paper put away in a safe place, but of course I couldn't find that safe place. So until I can buy a new supply (assuming carbon paper is even still available!), the final fitting of the bass bar will have to wait.
I used the remaining time yesterday morning in preparing some other wood for a Christmas present project I have in mind.