Frozen yogurt with inverted sugar
Yes, you’re right, invert sugar slows down the crystal formation and improves the texture of frozen products.

The way I use invert sugar in most frozen products is as a direct substitutue for the added sugar; for the frozen yogurt, it is no exception. You can just follow your recipe and replace the sugar with invert sugar by 80% to 100% of the weight of the original amount of the sugar.

Since the bonds between the glucose and fructose are broken, invert sugar is sweeter. It's of course a matter of taste, but I don’t think you'll notice a very big difference, even if you replace it 1:1.