Most everyone knows this, but if you are brand new to almost any kind of building project, this you should know. If you decide to use a regular carpenter "spirit" level for some of your building, like checking your CG, etc., make sure you check the level for accuracy - preferably at the store before you buy one and then frequently while using it. I won?t bore the masses with instructions how to do this - there are plenty of YouTube videos that show how it?s done.
Ed
