alloymach
Just line the back of the spinner plate with the front of the nose of the plane. The right thurst is built in and that'll be about right.
Just an observatioon but that 15X8 is only good for break-in and some say to not evendo that, but break it in with what you'll be flying it with.A 15X10 and you'll be happier, until you go to a 13X11 4blade
Eddie