Hi, I've only done one round (2 weeks ago)....just DMSA then added ALA 2 days into the round. It's fine to take ALA straight away alongside DMSA as long as you had your Amalgams removed at least 3 months ago and haven't had any recent exposure to mercury.
Some people do just start on DMSA for a few rounds (either weeks or months) to lessen the body burden before moving onto brain chelation with ALA. This seems to lessen the side effects of ALA chelation for some people.
I'm going to wait for a few weeks before doing another round and will just take ALA next time as I didn't seem to tolerate DMSA anyway, but will start very low eg 10-15mg.