Small amounts of licorice root every day should be fine as long as you don't have hypertension (and hopefully you never will!). If your potassium levels start getting low you'll feel weak and may have some abnormal heart rhythm.
Theoretically taurine should help myotonia because it decreases extracellular potassium and increases intracellular. That should stabilize the membrane and allow the cells to repolarize faster.
I tried taking it years ago and can't say that I noticed much difference, but maybe I didn't take enough. I think I just used one capsule a day and it may take more than that for a therapeutic dose. It certainly can't hurt to try and we would appreciate the feedback.
The recommended therapeutic dosage for taurine is .5 to 4 grams per day. I think the capsules are usually about 500 mg so you could safely take several.
I would say 2-3 capsules a day since one didn't seem to have much effect. I'll see if I can find out how much they used in the trials for myotonic dystrophy.
Since they're 1000 mg maybe start with one and see if you notice any change, and if not go to two.
I checked lots of articles and couldn't find anything on recommended dosage, so I guess you just have to experiment. I would suggest taking it before bed in case it makes your muscles really relaxed at first or lowers your blood pressure.
I'm glad you brought this up again - I only took 500 mg and didn't stick with it very long so maybe if I had increased the dose I would have seen more results. Someone wrote a post a while back about an energy drink that helped her myotonia and it also contained taurine.