Graphtech do quite a range of nuts that very in width depth and height. So it's worth measuring the current nut (which will invariable have the nuts too high) and seeing what their best fit nut is.

https://graphtech.com/pages/nuts

You then have to see if you can find a more local stockist (or an online provider) who has one of that type . Because there are so many sizes, very few music stores keep much of a range in stock, only the most popular ones, so don't think that's all there are available. And Graphtech can't cover every size combination, so sometimes a blank is the only option. But there should be one that is suitable for the kit without having to put a veneer shim in to raise it up.