I have used xanthan gum for years as a stablizer in home-made ice cream and it is fabulous. I have also used it in sauces and it is excellent for stablizing sauces and gravies, even acidic fruit sauces. Its characteristics include maintaining products through the freeze and thaw process. It is effective in dough products such as pie crusts and similar type wraps as well as the sauced contents. I have used it in fruit pies and meat pies.
I recommend that you use traditional starches as the basis for your thickening, including a small amount of xanthan gum to stablize and preserve the thickening. As you gain experience with it you might increase the quantity. It is considerably more expensive than traditional thickeners.
As to quantities, I have used as little as 1 tsp per 1/2 gal. fruit based ice cream, less in chocolate and vanilla ice creams. This is the most impressive place to use it, in my opinion. I routinely make home made ice cream that will remain frozen in my freezer for as long as it takes to eat it all, maintaining the same smooth, creamy consistency as the hour it was made. One particular chocolate recipe lasted nearly two weeks and retained the same silkiness you expect from the world's best high priced brands.
Best of luck.