Need?? Most anything store bought can be made. I just happen to have the CG machine and I had the throw meter they sell but when I have nothing better to do I pick up some of my scrap wood and make my own degree meters for setting my control throws. I make up a bunch and give them to friends. The CG machine can also be made and if you want a real slick one look up Vanessa as the key word and you will find the instructions for making one, a very good one right here on RCU.
All these items are nice to have but not really needed. A good ruler is your friend. A base board with some holes drilled into it and a pair of pencils makes a good CG machine.
A lot of ways to do the same thing without spending any money.