I'd purchased the RM1303 puller for use with my old Stihl 056 chainsaw, which used M5 bolts to attach the fanwheel and are also used for pulling the magneto flywheel. The problem was that the washers used on the smaller bolts supplied with the kit pulled through the slots at about 30 ft. lbs. of torque on the center bolt.
I went to my lathe and machined up some M5 shoulder bolts with large heads and found they did the trick. You may want to consider modifying the kit to include beefier attachment screws.