Yes, but REALLY a beginner, not just modesty…
…and my profile also says I’m a beginner and sadly that is not a sign of humility: I really AM a beginner.
So with my limited understanding I will tell you what I think is your question, and what I think MIGHT be the answer, but the truth is that I don’t know the answer because I do not yet do applications (sparring). Once I have achieved a certain level of skill then I will be able to learn applications but my root, my ‘ba’ step, my walking, turns, circle walking, posture, breathing, etc. have to be up to par and I will have to learn to be more sensitive as well first.
In terms of what approaches are used to deal with opponents, there is no one response; we are taught the principles and expected to apply them in a given situation - at times we are shown examples of how you might deal with a situation, but even then it is not the only possible response.
So, what I think from your posting that you are asking, is how to deal with someone grabbing your (arm?) with two hands. This would really depend on where you are in relation to them to begin with (as you say, pretty hard to describe in this forum). We also don’t use the terminology of ‘waist rotation’ because we actually turn at the hips and the terminology can be confusing (especially to beginners like me). As far as I can tell (from my perspective) we don’t train how to deal with specific situations but use principles such as the ‘ridge pole’ and ‘get off the line and go for the spine’ meaning (in this order) - that you keep your body alignment straight (this gets harder to describe the more I write!). The other principle I quoted is that let’s say in your example the bloke is coming directly at me and grabbing my arm. “Get off the line” is essentially an instruction to step out of his path (either into him or away from him but not in the same line as him) and “go for the spine” is how we train to take advantage of the opponent’s own movement. Wow I hate being a beginner; I’ve never tried to explain this to someone. There are many other principles (such as “ball and wedge”) and we are taught that if we learn to apply the principles, that is the groundwork we need in order to learn to deal with an attacker.
In terms of hand position once again it will all depend on the actual encounter. The hand/arm position will be unique to the circumstances - you could for example also use a technique of first having both arms going up (perhaps catching opponent under one of his arms with untrapped arm) then both going down while incorporating a turn and if he continues to hold on then he may fall down.
Or a completely different approach we have ‘played with’ (once again not yet actual sparring at my level) is something called the ‘brain blink’. With your free arm touch or push your attacker somewhere else and in that instant where his attention is not focussed on holding your arm, it is quite easy to extract yourself.
Sorry Dave if my answer is a bit disjointed. I hope with more learning on my part (a year or two more?) I can contribute more and give a better answer. For now, this is the best I can do.
Cheers
Sandy T.