As for the thumb, yes, definitely should not stick out.
Glad you brought Stephan back. He's fully researched this thumb business.
This Stephan guy still misses the mark, the types of hand form strikes are for instances to apply a technique you dont continuously hold that fist form and fight like that.
E.g Leopard Paw Style LoL
Thats not the intent of those fist forms.
What his missing to say in all honesty is that in the vicious fights of ancient times they would maul each other down with a variety of hard strikes to specific body target points, where each strike form was specifically designed for mostly in the later part of the fight wearing down the opponents.
Maul meaning..........
verb
past tense:
mauled; past participle:
mauled
(of an animal) wound (a person or animal) by scratching and tearing.
"a man was mauled by a lion at London Zoo"
synonyms: savage, attack, tear to pieces, lacerate, claw, mutilate, mangle, scratch
Link:-
https://www.google.com/search?client=firefox-b-d&q=Maul+meaning
The Karate and Kung Fu fist form strikes are alike in the two systems with the intent to cause outer bruising, scratching, tearing, and other types for internal blows to the nervous system and pressure point arteries.
They all work just as they are trained in and you can see the damage done without wearing gloves just in Bareknuckle fighting.
These days we live like civil people and behave, we train in a sport environment with gloves and we don't apply that amount of damage to each other.
To say they don't work and are useless is only admitting you don't know much about Martial Arts at all.
Now to emphasize straight or vertical punching is simply based on the systems principles of punching.
Anatomically Karate focuses on the shoulder to rear foot alignment based on its fighting principles.
Anatomically Wing Chun focuses on the elbow and economy of motion theory off a natural stance and also using a horse stance approach based on Kung Fu fighting principles.
In boxing both are used differently.
E.g...
* A straight jab - horizontal fist
* A right hook - vertical fist
One technique is applied and arms length range where another is in the pocket close quarter usually the vertical fist is applied here more like a piercing through the guard and gloves using the elbow. Some call it arrow strikes because like the tip of an arrow its intent is to strike the bulls eye.
They are precision strikes.... kidney, liver etc..... you cover these strikes in the second to fourth rank in TMA's as you start to develop in the art.