The problem with burning and dodging is repeatability. The masking method is of course repeatable, but takes time. I will throw one more method out there for you that is repeatable as well. If you have a diffusion enlarger and a glass neg. carrier you can do this. I tape the neg in the carrier then I tape a piece of frosted mylar on top of the carrier. Put it on a light table and with a pencil shade in the areas that you want to hold back. No muss no fuss and it works surprisingly well. Most importantly it is repeatable. Give it a shot.
Patrick