I just bought my son two of these raquets and I bought some big Ace for the mains. I just read the Head site where it says on their stringing instructions that you need 21' for the mains on this racquet. Have any of you strung the prestige MP from a reel and how many feet did you cut off? I would like to get two jobs from one packet of 40'. I know Head has some errors on it's web site for stringing instructions. Any replies appreciated.