Mentioning Sekiya reminded me of another student of Yamaguchi who used to say that it was impossible to do Ikkyo correctly unless you can make your hands heavy (he never said how, though..).
Yamaguchi used to also say..."Not soft enough"...
without ever saying what to do about it.
It is interesting to train with those who trained privately with him for over a decade and then...finally...having someone explain...what
Interesting that the one...solves the answer to the other issue you mentioned and why so few know the answer or different methods to train it!