Re: iwama kamae
I would say that it's not the butt that stick out but the hip that is "cocked". The problem I see with teaching the hip thing certain ways tend to be misunderstood. Take the "Iwama hip" thing. Go to a seminar with Iwama people and you will see a significant portion of them actually sticking their butt out like a duck. In this way they really lift the pelvic back and up. The hole idea, as I understand it of course, is to lower the hip in the cut (e.g. in 1st suburi). That is you lower the pelvic down and front by bending the knees, keeping the back foot at around 45 degree angle wrt. the forward foot. Both knees. If done correctly this leads to a balanced kamae that, if one relax, naturally lowers your point of gravity and projects small area forward.
Problem, as I see it, happens during the transmission of the kamae as a visual image to the student that only see the butt sticking out. "Ahh, I'm suppose to stick the butt out!", and proceed to do just that.
With the risk to sound zealous - Don't stick you butt out! Lower the hips, by bending your knees and tilting your pelvic down and forward.
I can't say that I know how H. Saito does things with respect to this. Since we are built differently some people will have to have their feet closer together in this kamae then others in order to remained balanced and centered. H. Saito seem to keep his feet closer together than most early students of M. Saito (and the founder). At least today. At my last seminars with Inagaki and Isoyama I think both keept their feet more apart.
When I started, I was always told, when doing tai no henko, to keep my head, back, hip, and back leg in one straight line, feet 1-2 foot apart. That is the optimal posture to project forward power (like when you're pushing a car etc). I was also told that tai no henko and 1st suburi posture should mirror each other. Today at seminars with Iwama instructors I frequently see a tilted back wrt. the leg. Both in 1st suburi and tai no henko. I can't say why this is.
Old movies of the founder and M. Saito always showed tai no henko made like I was taught. G. Shioda seem to have taught the same way (straight line, Yoshinkan folks anyone?). There seem to have been a developement and progression, perhaps when some aspects were focused opon more than others. (maybe like balans and moveability etc.).
However irrespective of the progression I feel both ways have solid foundation and are well thougth through. That is as long as one stick to one set of basics your body will learn well. Problem comes when one mixes basics and basic ideas that contradict each other at the early development training years.