Re: kamae problem
Kamae is an interesting issue for Aikido folks. I think we can basically talk about Kamae from three different standpoints. They are health, speed, and stability. As far as I am concerned, all three factors need to be considered.
Some of the "old style" kamae involve twisting of the foot to angles which any foot doctor will tell you is unhealthy for the knees. Stable, yes, but not healthy. So, I won't do that.
Some sword styles were designed to be done with armor. Their kamae tended to emphasize stable, balance movement because if you weren't stable, the weight of the armor alone could throw you off balance. Aikido folks don't tend to use these kamae except infrequently as movement is the hallmark of Aikido.
Some of the martial arts like kendo emphasize forward movement to the exclusion of everything else. So their kamae is designed for explosive forward movement and nothing else, not even stopping. Speed is the only real factor. Hips square, feet both forward.
Without getting into the many slight variations of Aikido hanmi, they all see to have some version of the front foot either straight forward or even turned out with the back foot ranging from 45 degrees to 90 degrees. I have see it all, and each teacher was fairly emphatic about about the "rightness" of the way they do it.
I would say that the practitioner shouldn't take much on simple faith. First look at the folks doing it as instructed... are they fast, are they slow, are they stable, or do they tip over easily? Aikido requires a stable platform that can be moved in an instant. It must be balanced and it must have the capacity for explosive movement without sacrificing stability.
I see very few folks who see to have worked this out. Folks tend to have either smooth movement or lots of stability. Each has issues. For the most part, Aikido folks are slow as molasses. Compared to other martial arts we move at slow speed. this is especially true of our weapons work but it is also true in our empty hand. We get very good at handling attacks from folks who can't move with both speed and power. It makes taking ones practice to a real high level almost impossible.
Rather than slavishly imitate another teacher's kamae, I would say really investigate what works for you. Find a stance that is stable, have folks push and pull from different angles and see if you really have a ground path. That's your platform for doing all your waza so it has to start there.
Then see if you can move quickly from that position without telegraphing your intentions with any preparatory movements. Can you simply move when required without extra weight shifts or loading movements? Most Aikido folks can't and it makes reading what you are about to do really easy for any experienced martial artist.
When you do move, do you have the kind of speed that would allow you to strike someone who didn't want to be struck? Otherwise, most of the practice is basically ersatz, with strikes that are wishful thinking rather than real.
If you look at how most Aikido folks stand, they are like a car at a drag race that is at the start but has the car in neutral. When the light turns green, the have to pushing the clutch, put the gear in gear, release the clutch, etc. The other guy is already down the course.
If your kamae is right for you, it should be possible to release your movement simply by picking up a foot, with no extra weight shifts or movements required. Pick up the front foot and you are exploding forward, pick up the back foot and you are zoning out. The whole body should be moving as a unit. Ideally, you should be able to move forward explosively and stop in an instant perfectly relaxed and capable of moving in any new direction as required. Weapons forms especially emphasize this principle but not many folks talk about it. Usually, the work is so slow you are not forced to really figure it out.
Anyway, I would investigate this issue for yourself and find what really works for you and is healthy as well. There is a lot of stuff out there that is, according to this or that style, quite correct, but really doesn't work from the standpoint of the three considerations mentioned.
Personally, I had to spend a lot of time on this myself because I was always so big. I am the super tanker guy. If I do not move efficiently I would be so slow as to make much of what needs to be done impossible. Even before I lost my weight, I was able to occasionally actually get my teacher when we did sword. It took me a lot of years to get to that point but it was the constant attempt to do so that made me figure out how to move and stand efficiently for me. Whether it's any more than generally applicable to someone else's body type, I think has to be answered my the practitioner himself.