Re: Tenkan - advanced
While my partner is still a ways away from me (more than one step) I row forward a little and extend my arm, offering them a target. As they approach I row back, imagining drawing energy out from their center. This helps to establish musubi. As my weight shifts to my back leg, I move my forward foot to the side (not in) just a little so that when I pivot on it my partner can continue along their line uninterrupted.
My goal is to establish a good connection and then move myself with good timing, posture, etc. and not worry about moving them. If everything goes well, they will move past me. If not, then I have to keep practicing.
It is certainly possible to do tenkan where nage keeps their own line and moves uke around them - that's useful practice too. But the above is what I'm working on now....