Either player may use a computer for playing advice. Not the striker. It is a fault if the striker touches his own ball to move it into position for a croquet stroke before quitting his stance from the previous stroke. This is indistinguishable from retouching during the striking period which is a fault. It is illegal for the opponent to assist the striker by offering genuine advice, even in social play.
Advice can be indistinguishable from gamesmanship.
Playing to a time limit in a non-tournament game is illegal. The players can do what they wish. They can always treat their game as a match covered by Law 53. Only if he does not realise that he is already looking at Law 28. Intended to cater for an extremely rare situation where the striker gains a significant advantage as a result, but the change will simply penalise inexperienced players and make the laws more complex.