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.