You have been touring with a triple crank. How do you like it? How much time do you spend in the middle ring?

If a 46t will fit for the majority of your riding that is fine, but if you really want that tweener chainring, you’ll need to figure out what will work for slogging thousands of miles.

You might also want to post this on the touring sub-forum and get their feedback. Having some real life experience by someone who has toured on a Checkpoint might give better insight.

The shop may also be able to track down a 60cm 520 through their systems.

John