I have always seen this line performed with an emphasis on You. It is definitely the most logical choice. But it’s funny, in looking at it – it is really just the same line repeated – Hamlet could repeat Polonius’ line exactly as he said it. He could mock him as he says it. He could say it simultaneously or a fraction of a second after as a means of demonstrating how predictable Polonius can be. He could say it to Rosencrantz and Guildenstern still in their private circle.
It’s always nice to have more than one choice – even if you end up doing it the same way everyone’s done it for centuries.