Struggled with 1:1 dosing for years myself. It was only when I had a long conversation with Randy did I realize I should be dosing 1:1 and would not see the relatively small drop in calcium in relation to my ALK.
Even if you test kit says not to add calcium, still dose in a 1:1 ratio. Even though my test kit says my CAL is 440, if I'm adding 37ml of ALK, I add 37ml of Cal, and guess what? My ALK is stable, and so is my cal even though according to my test kit I do not need any CAL.
Same goes for MAG. Once you use up a gallon of 2 part, add the gallon of MAG even though your test kit says it 1350. If you add it all like your supposed to, you will not see a rise in MAG like you think you would.
Odd I know, and it took me a long while to wrap my head around it.
EDIT:
There are some 2 part products out there that are not dosed in a 1:1 ratio, but 99% of them are.