I used a straight piece of metal slightly thinner than the width of the slots and added shims until there was no movement of either cam. This worked for me.(Maybe I got lucky)
I first tried to eyeball the slots but due to spring pressure on the cam lobes, they would not line up (about 1/2 tooth off location.) I think 2 people could probably do it with 1 person using wrenches on the hex shoulders on the cam shafts to manually line up the slots while the other person installs the belt. I didn't have any help, or the proper tool, so I had to come up with a way to align and hold the slots in place while I installed the new belt. Don't know if this will help, but it's what I did.
