No worries. I used an all in one paint primer by Dutch Boy. Its an interior latex satin enamel. I did one coat. let it dry for a couple days, then hit it with 220 grit and then one more coat. Thats it. I used a .25 inch think MDF for the letters.
couple more pics of progress.
the blue letters are not permanently in place yet. I have some dividers I am going to be putting in between each line.
Looks amazing , you did a fantastic job here and should be proud of this work.