It was about as time-consuming as I expected (probably about 2 hours per sign).
1) Use a nifty font website to create your template. I used Dafont.com and downloaded a bunch of fonts and made my templates in Word.
2) Once you get them juuuuust right, print them off. On the back side (the side that doesn't have the font), shade behind all of the words with pencil. You'll be making a transfer. Looking back, I should have tried using white colored pencil for the transfers I was planning on doing on the green canvases. I could barely make out the pencil.
3) Paint your canvases.
4) I put a book under my canvases during the transfer so that my pencil wouldn't stretch the canvases or leave dents (Game of Thrones is both a good read and a good crafting tool) and traced the letters, pressing down hard, to transfer the lead from the back side of the paper onto the canvas.
5) I used Sharpies to fill in the letters I traced. It was much easier than paint and I had more control. I used silver and gold markers on the green and red canvases. It was pretty easy to tackle a canvas or two while Bubby was napping.