I tried making some Low-Carb Chocolate the other day. I used:

2 squares Unsweetened Baking Chocolate
1-2/3 Tbsp (24g) Coconut Oil
1-2/3 Tbsp (24g) Carb Countdown Whole Milk
1/2 tsp Stevia Extract Powder
1/2 Tbsp Liquid Saccharine

Adjusted to the amount of Chocolate you used, that would mean I used 3x as much Sugar Substitute as the recipe above called for. Mine came out kinda Bitter-Sweet, but the consistency was good. I'll try it again with less Stevia/Saccharine and see how they turn out. I might omit the Saccharine this time and just use all Stevia...I wonder how that'll effect the consistency ??? I've been trying to find PURE Cocoa Butter, as that's what's used in Real Milk Chocolate, but no such luck. All I've been able to find is Cocoa Butter made for Beauty Treatments that's got all kinds of other ingredients in it.