triple glazed to N,E and W, double to South.
Not sure why you’d do that. Triple glazing really doesn’t add much cost over double on the total price of a job (with the same quality frames).
Sound insulation is slightly better, insulation value is better though not as much as you’d think (theres a huge change in these from single to double, not so much from double to triple). The main benefit comes from the inner pane being a few degrees warmer – that means you get less convection and draughts within the room, and can sit closer to the window without feeling a drop in temperature.
All has much more impact in a well insulated, airtight, house – much less benefit if it’s leaky an poorly insulated (or If you still fit trickle vents to make airtight windows draughty and by pass the sound barrier)
3g windows throughout our place.