peg board probably works great. If it were me, i would use a sharpie to highlight a grid on the peg board, making squares of maybe 4" per side...
i'm glad to see you built your tillering tree. I was just about to post the question, "Got that sucker built yet?" I gave mine away to a new guy, Mar, last fall, and when i get home to Canada i'll have to make a new one. They are pretty handy, amigo.
If you are new, make sure to read as much about the actual process of tillering so as to get the most benefit from your tree. If you want, i'll write a couple paragraphs in this thread to describe how i do it, which i "think" is a pretty common practice.