Working off of the hamalas salt extraction. I have the salts redissolved and filtering in 500ml of water, 100ml of white vinegar. Anyone have an approximate or exact amount of sodium bicarbonate for precipitation of the alkaloids? I would prefer to get the NaHCO3 as exact as possible to keep it out of precipitate.

Add as much as you want really, the vast majority of harmalas will precipitate out long before the solution becomes saturated.
"Keep adding until the color stops changing" is an adequate guide.

I have been following that guide and I seem to always go to far. I will play with it, add measured amounts and just remember it.