Hello,
interesting idea, I have an obvious question: how would illegal moves be handled?
For example, if the pre-move is a pawn move but the opponent's last move is such that the pawn cannot move (blocked), what would happen?
It could give crucial information on the opponent's last move if one's was allowed to try another pre-move.
Standard rules except you have to pre-move every move. The way this works is you don't see the opponent's move until after your pre-move is submitted, but your clock starts ticking once their move is submitted to the server. Another way to think of this is like a limited Fog where you can see everything except their most recent move.