Getting correct baking consistency when using stevia as sugar substitute

Not really, unless you go for a different carbohydrate with physical properties similar to refined sucrose. And if you are removing the sugar for dietary reasons, you're probably not winning anything by doing the substitution.

Artificial sweeteners and stevia are just that - a sweetener, not a sugar. They can only be successfully used as a substitute where table sugar is used as a sweeteners. For example, they work well in a coffee or a homemade lemonade.

In baking, sugar is not used primarily to make the batter sweet, in fact it often makes it too sweet for my own taste. Its purpose is to provide structure. It has unique physical properties it shares with other short carbohydrates, but not with non-sugar sweeteners. You cannot substitute sugar for something which is completely unlike sugar and expect to get the same result.

If you are very adventurous, you can try using soluble fibre in place of sugar. But it's hard for a home cook to 1) get a supply of it, and 2) tweak a recipe such that it works well enough texturewise.

If my assumption is wrong and you are not counting calories, it becomes easier. Adding pure glucose or fructose will produce a recipe which still needs a tweaking, but can potentially be made similar to a sugar-containing one. Then you should also leave out the stevia, because it will make the bisquits overly sweet.

I've successfully used apple fiber with paleo brownies. Where 1/3 cup of honey was called for, used about 1/2 that amount of the apple fiber with powered stevia to taste.