According to Guy Fletcher, the songs on which Mark plays the Tone King Imperial are:

True love will never fade
Shangri la
Prairie wedding
Dark is the night/Donegan’s Gone
Postcards from Paraguay
Let It All Go

I guess this is meant to be true rather for the latest tours than for the studio albums (click here to find out what gear was used on them), and it matches what I described in this blog post:
Which songs of the Get Lucky tour are played with the Tone King Imperial? And what was the amp setting?

However, we can add the songs Prairie Wedding and Let it all go (which was only rarely played live, I think only on some of the small promo tours) to our previous list.