The difference in carbs between 70% and 85% dark chocolate is considerable. My favourite is the Aldi stocked Moser Roth 85% which is only 18g carbs per 100g and has a really deep, smooth chocolate flavour.
I've just ordered a bar of the Lindt 85% in my shopping. Will be first chocolate since diagnosis. To date have not dared to buy any as self control is usually an issue if there is any in the house. Hoping I have improved that over the past few months.