Probably the most useful thing I'll ever print.
Rather than print out the letters, I'll get some black fingernail polish to paint the recessed letters.
With the R2X I inserted the letters in the model just before printing and used the dual extruders. I hadn't thought about printing them out separately and then inserting them into the final model. I'm not sure they will fit, since printing seems to increase the final size. I guess because of spreading.
Glad I didn't try it then, I don't have a dual extruder (yet). :)