Ok Yoshi/Clarence...
Give me something else to go with because from what I see, and from what I understand to be a use of 'triangle palm', they are poles apart...
Firstly - The SEED of Tan, Fook and Bong as shown in the Dummy pics is rotated in sequence during this type of interaction, and Stan is not doing this. His basic level is very evident as he swings back and forth repeating the SEED in/out etc rather than staying to the method you talk of and then, to make matters worse, he starts to 'dive-in' to a loose 'Sansau attack method. Not good imho.
Secondly - The SEED relates directly to the 'techniques' of Mun, Wu and Gaan buut you need to understand the posturing first and exactly what the supporting hand is doing. Stan does not seem to be connected to this idea at all.
Third and finally - There are various ways of interpreting the 'traingle palm' method. One: you create a triangle of 'intent' at the back/base of the thumb to project a traingular shape of the hand in each SEED. Two: there is a refernce from my own training where this triangle is related directly to the contact target ie. the bends of elbows/knees, the under arms etc called 'saam gok jeung' which is trained specifically on our Mook Yan Jong.
I do not have a problem with the quality/standard of Wing Chun in Stans clips. he is simply doing what he is doing. BUT when you have many many people who have dedicated more than half their lives to the system it tends to get a bit tedious seeing such levels of skill (or lack of) being touted as 'Sifu' quality. And if you are his SiHing, I would hold YOU responsible for his standard lol!!
So, rather than pummeling the boards with all these threads, I would ask that you pay Stan a visit and work harder at raising HIS game if he wants to be taken seriously as a Sifu in this big bad World of Wing Chun today