In this pic it seems only the pressure of the thumb pressing down supports the pointy index finger and so I cannot fathom how great power, let alone max power could be used. Not saying you can't but I don't see how.
Despite the fact that WCK has shokens in the forms etc, we never trained them. Ip Man tossed them out of the system when he began teaching in Hong Kong and replaced it with the also existing Chung Choi or vertical fist leading with the bottom pointy knuckle.
I cannot fathom use of the shoken *for me* but I have played with it a little and never liked it and I cannot apply any great power with this fist. I was taught that the thumb goes in behind the index finger supporting it. In any case I cannot use max power with hardly any fist compared to a palm heel because with the palm heel there is nothing to break or flex and the shoken seems the least stable of all the fists, to me.
There is a different version of this pointy thing from a Korean Art where the index finger (same knuckle) is used but the first part of the index finger is straight and aligned with the hand, kind of like a trigger finger position. With this I can easily poke holes in boxes, etc but I do not train it for SD.