Depending on where you are in the world, you might consider the folks who post the hair tests of members of heavy metal detox groups--livingnetworks. They have a good reputation in the detox groups. Their price might be low enough to allow you to alternate weekends and therefore keep your gut bugs from becoming problematic.

Then again, you might be like me who has done fine with DMSA + LA; however I mostly have a lead and cadmium problem.

I think it is wise to do a couple of rounds or maybe more with just DMSA or DMPS. This will give you a feel for your reaction to one chelator before adding the second.

ALA tends to kick butt if taken in excess in a person with an heavy metal--HM problem. So it is nice to get a feel for your tolerated dose of another chelator before adding LA.

Additionally DMSA and DMPS work mostly in the blood stream, not organs, brain. ALA has wide access to organs in the body and can move HMs both directions--out and in! Therefore clearing the blood stream before adding LA seems wise. This is one of the principles involved in AC protocol.

Good luck.