You cannot do manske on basic solution. Manske precipitates HCl salts, which means you need protons.
Manske works by shifting equilibrium. It is called Le Chatelier's principle.
Adding an excess of chloride ions to an acidic solution of alkaloids, the system will compensate to try and get rid of some of those ions by precipitating the less soluble protonated harmala chloride salts.
---
didn't read your whole post, if the pH is not too high and there are still harmala salts, manske can work. Keep in mind manske does not precipitate to completion nearly as much as raising to the pH to 10 does. Manske might get you some harmaline at pH 8-8.5, but you already pushed it to 10 so I wouldnt expect much of anything. Manske is an excellent way to get high purity harmalas as a step before basification, sacrificing a bit of yield (not much, maybe 5-10%).
Expect nothing, Receive everything.
"Experiment and extrapolation is the only means the organic chemists (humans) currrently have - in contrast to "God" (and possibly R. B. Woodward). "
He alone sees truly who sees the Absolute the same in every creature...seeing the same Absolute everywhere, he does not harm himself or others. - The Bhagavad Gita
"The most beautiful thing we can experience, is the mysterious. The source of all true art and science."