That’s what they do in go and it makes more sense than a fixed pause after 25 moves.
Or if you want to really force people to think for 5 minutes you could make it a 5 minutes every 5 moves—then you can use your 5 minutes to really map out your options for the next 5 moves before the next pause. And it may even be a good training for chess players, avoiding to waste time by redoing the same calculations move after move.
That’s what they do in go and it makes more sense than a fixed pause after 25 moves. Or if you want to really force people to think for 5 minutes you could make it a 5 minutes every 5 moves—then you can use your 5 minutes to really map out your options for the next 5 moves before the next pause. And it may even be a good training for chess players, avoiding to waste time by redoing the same calculations move after move.