Rather than overcomplicating things, I decided to go with a very simple homemade spring to hold the points on my hand laid turnouts. As you can see from the photos, the spring is a piece of .028" brass wire bent to a 90-degree angle with two "legs" bent downward. These legs are inserted in holes drilled in the throw bar and an adjoining tie.
Once the turnout is finished, painted, weathered, and ballasted, I think it will be virtually invisible. If I want to take a realistic photo of the scene at some point it's a simple matter to remove the spring and replace it once the pictures have been taken.
Thanks to all who commented with suggestions - the "spring" you see here is actually the result of some experimentation over the last couple of nights. I'm pleased with how well it works. Sometimes the simplest solutions are the best.