The short answer:
You should make a salt of the arecoline-derived cocaine analog, preferentially the HCl salt.
The long answer:
Most drugs are basic amines, and are thus corrosive to your mucous membranes and cannot usually be ingested as is. They are also very often oils (hard to measure correctly). Therefore, a salt of the amine is made, so that it will become easier to measure out and to ingest. The reason the HCl salt most often is used is that it is non-toxic, cheap to make, it usually formes nice, stable crystals and that HCl is one of the lightest acids there is per unit - so that the ratio of drug to salt-forming acid is as high as possible, so that you don't need to ingest an unnecessary large volume of powder.
For different reasons, there are exceptions to this rule - for example, the HCl salt of amphetamine is hygroscopic (draws water from the air), therefore the sulfate is usually made instead. the HCl salt of DMT is hard to crystallize, so the waxy freebase is used instead (for smoking) or the fumarate (for injection). In the case of LSD, the HCl salt is not as stable on storage as the tartrate, so most often the latter is found in that form on blotters or microdots. The sulfate salt of mescaline is easy to purify and gives wonderful large crystals, so therefore that is the common form of that drug.
