Jsman - The output of the Dyna 20X may allow you to use either the MC or MM sections of your preamp. It would be interesting to see which phonostage you prefer.
If you also use a JMW arm with your Scoutmaster, then take advantage of being able to compare cartridges via interchangable armwands. So when you have another, identical armwand you can see if you enjoy your new MC more than your AT 440MLa.