Those are good instructions, g.willikers, asnd not he ones I had seen. Using the dremel for which inexpensive wheels for cutting practice are available is a good idea.
I think I'd rather save the original stock for my <5'10" son to whom I have promised the gun if I buy another.
If a shorter stock indeed is warranted, I will spend the $60. It cost me more than that for ammo, fees, and gas the last time I shot (when I almost certainly further imbedded bad habits into muscle memory.)