So, was chatting to Si Fu (please DON'T take my words as any strong representative of his understanding/application), wouldn't use the 1000 hand against a punch really, movement is big & low, we have plenty of other stuff for punches. If you did shorten the mechanics of the 1000 hand against a punch into a short power type thing, sort of getting on the trajectory for a moment to deflect a higher strike it makes sense to me to go straight in with the same hand to attack imo - on the inside mirroring your opponent's side this makes sense as if deflected properly they would prob have to go in for the 2 of the 1-2 with the other hand so your backhand can cover; on their outside you should be good to go, deflect & in for the strike with the same hand used - quicker for you than also doing a 1-2; even though you can chuck both in together. Footwork & positioning of course important. Hope this is making sense... theorising is just theorising. We'd use the 1000 hand for a low strike or kick instead, then can launch in from low upwards if need be. Form trains body mechanics & speed, this follow up part not really for trading shots, just attack if the going's good. We have & train it both sides, so can adapt for the positioning, front hand can cover defensively & offensively, as can the back hand transition. Workable & adaptable inside & out depending on reading of situation. Found a pic from filming day for a basic static structural reference:
Does pic raise any issues? I think front hand can adapt to cover upwards quickly, but is more offensive. We often applicate & strike a couple moves with same hand. My words don't do his demo or explanations to me much justice, things are much harder in textual forums than in person. So much stuff in the forms adaptable, the reaction conditioning aspect important here, down & then in shortest reaction possible, front lead aids this I think. 1000 hand into palm previous just basic conditioning for strike. My speed in video no justice for app if you were to attempt anything in exact form order (we're not really, just intent principles). My understanding prone to change; I feel how I can work this way though.