Harmalas HCl (or any other salt form) is indeed usable sublingually, but do not taste great. I would recommend you to convert it to freebase for sublingual use. In this form, rue alkaloids are just slightly bitter (and caapi freebase is almost tasteless) and its use is really convenient.
Indeed, but part of the sub-lingual use falls into daily-use category, smaller doses throughout the day, or some each night... or every few days... just, regular use is common with sub-lingual administration...
Freebase is slightly caustic and can burn and be problematic over time... plus the absorption is a bit improved with HCL salts...
But yes, for single-use sessions, freebase does work...