rOm, I'd also be interested to see references for your claims that those other alkaloids don't form salts with HCl.
Could it be they do form HCl salts, but those salts are fairly water soluble and therefore don't precipitate straight away - but evaporating the water / HCl would allow one to retrieve them?
If they don't form salts with HCl, how did the HCl soaks pull them in the first place?
Do they form salts with any acid at all?
If proceeding to salt the freebase with HCl, could the acetone step be skipped and the crude freebase be salted with dilute HCl directly?
I'm doing a small (POC size) extraction, have based the vinegar pulls with ammonia to pH 10.3, will be collecting the precips soon. After that, the plan is to add NaOH to the supernatant to see if more alks get pushed out.