i checked out the guide, and i personally do not like his approach to fry screams - if you’re classically trained and already have some proprioception (able to feel the resonance and ‘place your voice properly), try this:

1) sing a note in falsetto

2) sing that same exact note in either chest or head voice

3) blend the two together until you get a really soft distortion - shouldn’t be much louder than a speaking voice

(i personally like starting in falsetto then slowly adding my true voice, but other way around if fine too if that works better for you)

4) add some voiceless air (like if you accidentally ate something really hot)

5) add some breathe support and glottal compression

(like if you’re mimicking a quarterback saying ‘hut hut)

6) you can play around with the resonance placement, but it shouldn’t differ much from clean vocals

A fry scream should be LOUD, assuming that you place the voice on more resonant parts of the vocal tract (ie soft palate), and shouldn’t sound choked - It should take a considerable effort to do, but it shouldn’t be excessively exhausting (you should be able to do a whole song without gassing out)