Re: Jo tsuki
I have one problem with self-experimentation, our conclusions are normally biased by your way of training. So, be careful of making concrete conclusions.
The things I practiced a lot are much easier for me then those I try for the first time. As we practice, we improve our coordination of specific actions, much more then our general coordination, so, doing things like you learnt, or along the same lines is always much easier then the other way around, regardless of the matter at test.
And this comes from someone who has learned both ways of applying a Jo chuki, with the front hand almost static (at the end of the trust) and with it participating in the push till the end. Each such method has its uses, depending on your initial state and purpose.