ok, follow this,
1 mg = 1000 mcg
let's say you have 1 mg of M2 in your vial. If you add 1 ml of Bac water, then each 10 iu on the insulin syg. will have 100 mcg of M2.
if you have 10 mg of M2 in your vial (and used 1 ml of Bac) => each 10 iu on the insulin syg. will have 1000 mcg of M2.
if i were you, i would adjust the amount of Bac according to the dose you need to make it simple when drawing.