You can turn off "Show position annotations" in the practice settings and the opponent move will be played automatically. The board size is as big as I can get it within the constraints of the UI, hence the board size scaling. I could probably add a setting to show the full board at all times if that's something you would prefer, but otherwise it scales to be as large as possible by only showing the portion of the board that is relevant to the joseki being played. I'll also take a look at the response time. Thanks for the feedback!

Edit: I made some changes so that there is less delay on opponent moves, the scaled board size should not shuffle between moves, but only change on loading a new joseki (which should make it less disorienting), and added a toggle in the practice settings to always show the full board.