I have not cropped this to emphasize the lettering because I want you to be been to see and study how the letters fit into and onto a band of ornament as part of a curved mosaic surface.
It also shows a good color balance in the composition and layout.
Think about how a similar color layout might work in print or on the web for a title or header or poster. I think you might have to strengthen the greens for modern mediumand maybe darken the blue or strengthen it?
You don't have to do a ChiRho ... you can experiment with other letters! Initials maybe?