I am about to place an order for the Electro Hub in a day or two. I have watched the build video several times and nowhere do they mention the size drill bit used for the holes for mounting the booms. I am new at building multi rotors, and I am also (somewhat) new at using power tools on a regular basis. I have all of the needed tools, I just don't know which drill bit to use for the mounting holes for the booms. Any help would be great. Otherwise, I am down to just drilling holes in something until I find a hole the right size. Trying to save some trees here.