What they are after is alittle pre-load on the bearings when assembling the unit. Find what ever you can that fits the splines. Any old 12 point sockets laying around?
You might be able to set up a pull type scale ( fish scale ) and some vise-grips, attach the vise-grips to the shaft and pull the fish scale which is hooked to the end of the vise-grips reading the scale as you pull, if they are 12" long your scale would be pretty accurate. Don't forget, the on center preload will be tighter then the ends. On center is tight to keep it from wondering around when going straight. It should say somewhere to be off center when adjusting, then cross center to check to be sure its not to tight. Joe