Guys like Tim Larkin are just gimmick teachers. There are a bunch of them. Its not as though he wont be able to give you some decent fighting tips, but he isnt training real killers. His students are all beginners who dont know anything. He has never produced a world champion fighter. Credentials matter a lot in martial arts. If he doesnt have any elite students, then how good of a teacher can he really be?
If you want to learn stuff as a hobby, go ahead, there is nothing wrong with that, but a hobbyist instructor is not an authority on fighting. The best martial arts teachers do not spend their time on youtube. They are WAY too busy for that.
Rule of thumb for old timers... forget everything you knew and learned before the year 2000. Virtually all of it is horseshit. That is a tough pill to swallow for most people, but i swallowed it years ago. Tae Kwon Do is a middling tier martial art at best. Thats what i wasted my time with. I had to come to terms with that. Its going to be even harder for kung fu guys because kung fu is COMPLETE horseshit. The stance is retarded, the offense is retarded, the entire art is just stupid and useless.