I'll add that if you have a stubborn flywheel, buy a $8 rubber mallet -a must.
When you get good tension on the puller, rap the flywheel with the rubber mallet. You may have to wack it a few times. or so. If still stuck, tighten, wack a few more times.
I've also used a 3 jaw puller to get them off.
Make sure the jaws can get seated well, then same deal.
And yes, his instructions are the norm for a back yard mechanic pulling an upper seal. Suck out any chips. I've also drilled partway, then used a 10d nail to punch a small hole(no chips). There's lots of ways to do it.
Now the, "No-hitty on the flywheel" Nazi's will have a Hit-man out looking for me - not to mention the 3 jaw puller!!!
Use advice as you see fit, done hundreds of times and no damage ever.
Just curious, when you had the flywheel off, did you see any oil under it?