It can be done, the biggest concern would be because you're doubling the weight of the glass you will need a heavier weight which you may struggle to fit in the box. Typically on the older windows round cast iron weights are used and you can fit a square steel or lead weight which gives you more weight for the space it occupies as opposed to round weights. I have seen people jacket old cast iron weights with roofing lead, but this is a bit of a bodge way of doing it.
You can get 12mm krypton-filled units with an 8mm sightline around the perimeter so that they suit traditional sashes, but these are very temperamental and don't have the best service life, you'll be very lucky if you don't have one fail within a couple of years or less. I prefer 16mm units for such work but you have a larger sightline which requires a 15mm rebate which may look out of place, and also you need to produce plant-on bars stuck on with double sided tape to cover duplex bars inside the glass, rather than traditional glazing bars as because of the rebate depth requirement your glazing bars will become 36mm rather than the traditional 18-22mm.
If you want to go for 24mm units for the full benefit of double glazing, you can rebate the faces of the sashes so that they project past the inner and outer linings of the sash box, so it would be ~55mm sash fitting into a ~44mm run because you've rebated the sides and top of the sash to suit. One of the biggest benefits you can achieve when replacing sashes is adding draught-sealing if there isn't any existing on the sashes, I use the Deventer sash flipper on the sides of the sash, Aquamac 21 on the top rail, bottom rail, and across the grain on the edge of the sash near the bottom rail on the bottom sash and at the horn on the top sash so no draughts run up the side of the sash and the pulley hole, and Aquamac 63 along the meeting rail.
