What size of shaft packing for '65 Skier?

Its the rubber insert in the strut. You can get them at skidim.com.

I do not remember the size of the packing but here is what I would do. Unbolt the the coupler and remove it from the shaft. Remove the stuffing box from the log. I would go ahead and replace the rubber hose portion of the log if it has never been done. Mine crumbled when I removed it. Once you remove the stuffing nut you can pull the stuffing out. There will be 3 or 4 pieces inside. Keep at least one so that when you cut the new pieces you have a guide. Once you see how they are packed in there it is pretty straight forward putting the new back in. Just stagger the breaks so water does not have a direct path and keep everything nice and square.

Once reinstalled you probably will not have to tighten it very much at first. Mine drips 3 or 4 times a minute and stays cool. You want to find a happy medium between too many drips and getting too hot. You should be able to hold your hand on it comfortably. If you burn up the wax it will start to leak too much. May have to tighten after a few hours of use.

I think there are only 2 sizes of stuffing. Get both if your not sure. Its pretty cheap stuff.

Also might as well replace your cutlass bearing while you have the shaft apart. Especially if you have never done that before either.