Don't hesitate to lower the dose if you feel it's too much. Some people does fine at 25mg, other people have to start at 12mg or even 6mg. Just try to see how you feel.
Also I take it every 4 hours but some do better every 3 hours. It depends how long it will take you to metabolize DMSA. Wait to long between 2 doses allow the redistribution. Start at 25mg and see whre it goes.
Have a look on Andy cutler frequent doses chelation yahoo group. Read some post. People are even more active than on the curezone candida support.