Im 31 with mercury toxicity and moderate lead toxicity as well. No amalgrams. Your symptom sound like mine. I had the dmps challenge Iv test.
If you want to do chlorella, 3000mg is a good dose per day on empty stomach.
Ala is good to do alone or with dmsa. I would almost do some frequent dosing with that bc you don't know your mercury burden yet. I wouldn't want you to dump too much with high dosage. So start with 12.5 every 3 hrs. If you do ok then go up to 25mg. I know you didn't want to frequent dose but that is just my opinion on how I would take it.
Dr. Mark Hyman has a protocol that is dmsa 100mgs 3x a day for 3 days. He suffered from mercury as well. So that is an option.
Either way you decide to chelate I would definitely take glutathione precursors. You can learn the importance of this by watching videos from Dr. Chris Shade who also had mercury poisoning. I just purchased MaxGXL on amazon which has a blend of the precursors. This is to make sure the mercury will detox correctly out of body instead of recirculate. Its the mother of antioxidants in your body. Very important.
Also take vit c, mag, zinc, selenium, and a purified fish oil!