The deadline would be changed to be whatever the limit currently is. Last to move - start next turn, deadline = 1 day from now (or whatever the limit is). You would always have at least that amount of time between moves, so if I move now I would never have to move again until 1 day from now, if that is the limit.
SURELY this is the same as existing games, if you are a slow mover choose a pond with a longer limit.
An option would be fine of course, you could choose the pond that suits you best or create one.