When I suggested using a chess clock in another thread I didn't mean to use it to manage time but as an indication of when you were finished.
You could use anything. A bell, a Turn Token like Firefly the board game, a BB-8 squeeze toy, a flaming torch. What ever can be used to show the other guy that you had finished what you were doing and he can start his action.
I suggested the chess clock because I thought it would be a good example. I was wrong ☹️