Your tone is pretty insulting. You're implying that we can't explain our own system. I chose not to reply because I didn't feel the need to spoon feed you. You're happy now because LFJ's explanation makes sense to you but only because it fits with your understanding. Ok, I'll bite, where the hands are held in a pre-fight/guard posture is always going to be based on personal preference and on what I need to do in that moment of time.
If I'm suddenly under a barrage I may feel the need to utilise a covering strategy before being able to extend my bridges/structure into my opponent. The idea of a fixed static guard is nonsensical to me, I will always be moving,enticing and enquiring (these are some of our methods you so kindly pointed out about 100 pages ago). I'm not thinking "better use double prayer hand from Bil jee) I use the mechanics/methods that seem appropriate to me at that point in time. Experience will often dictate my choices here not logic and theory. Don't be so fixated on guard positions, what truly matters is what happens when the hands start flying. We seem to do ok at that point.