Ultrabullet is just a shorter time control than bullet chess. Nothing changes in the chess rules. It might be good to premove when you can. You can use mouse. I don't think there is anything faster than a mouse. Touch screen is slower. Move confirmation is automatically disabled. Might want to shrink the chessboard to save travel time moving pieces. The less details the pieces and chessboard has the better it is. Play what you know, it's quicker.