Well, Walt has 2 methods that he will share with you, if you send him an e-mail.
I don't believe Walt himself has stated you don't have to remove the head, I believe he has stated that he has a method for REPAIRING the existing head without REPLACING it, which is how Briggs wants you to do it.
One method definitely requires removing the head and then removing the valve guide for some "machine work".
The machine work can easily be improvised using fairly common tools and patience.
The other method is a "trick" using some form of arc welding.
The method of arc welding described by the author of that fix uses a genuine MIG welder.
His method does not "require" removal of the head because he is welding through the exhaust port of the head with the exhaust pipes removed for access.
My opinion is that the welding method IS NOT something that a novice should attempt.
Walt will surely share his info with you.
But you will have to send him an e-mail and explain what you are trying to do.
His e-mail, is wconner5 at frontier dot com Put that into proper e-mail format by using @ instead of at, and . instead of dot and it will work.
Walt does not publish his e-mail address in a way that can be picked up by internet malware.

Sounds like if I am going to have to remove the head anyway I would be better off replacing it. I will have to order one for $100. Thank You

Checked valve reset clearance still very noisy can I operate it like this 154 hrs 8 years old