I know I am not going to get this overnight and might take 4 years or so to figure this out... but I am not even making a tiny bit of progress with my hands. ( I know i shouldn't be moving with my hands and thus that is where moving from center comes into play. ) I am trying to do a slight amount of shikko stuff and also trying to do things that require me to lower my hamni stance. I am by no means discouraged or heartbroken that I haven't figured this out yet. I am a very determined person and that is why I am asking others for what they think. .
Dear mary, I can hear your determination & frustration :-)
It sound`s like your problem is two fold.
Do not do aikido with emphasis on hands, or feet, or shoulder`s or strength. Harmony and the eventual realization of moving from your centre is the most efficient way to create harmony, in an Aikido sense is to use complete body movements.
Put another way, using your example of tai no henko, Your hands must be on the centre line to deflect the in-coming enrgy downwards. You must enter with your foot, slightly lower the knees, and pivot and the front foot whilst turning you palms upwards. this is basically it. when done as a whole and not really thinking about it too much you will feel it with clarity, which leads me nicely on to my next point.
Conceptualization, everytime you practice you make progresss even if you dont see it or feel it, but I bet your instructors do. Dont be too hard on yourself, let progress come naturally through dilligent persistent training and it will come. I like the NIKE slogan, Just do it! my teacher repeated this phrase to me over and over and over again for about two years then one day whilst holding a sword practicing the first bokken suburi, and happo giri(eight directional cutting), bang it just hit me, its much easier to move using whole body movements. Its also easier to move another person too!
Too much thought on hands, too much thought on feet, too much thought on breathing, to much thought on blending, too much thought on enemy. Where is your Aikido? No mind