I don't actually know what a Ksp is but I have had some success extracting rue. The method I have settled on is this: grind up enough seed to pack the basket of a stovetop espresso maker fill the bottom with H2O and 1/4 vinegar screw the top down over a piece of fliter paper, run the vinegar/H2O through and repeat 2 more times with new H2O/vinegar leaving the ground seeds in the basket. Combine the three extractions in a tallish jar and basify with a saturated lye solution, allow the precipitate to settle overnight and decant, wash the precipitate with more H2O (fill the jar) allow to settle and decant again. I then disolve precipitate in vinegar/H2O re-filter re-basify re-decant and dry. If you wanted to seperate the harmaline from the harmine you can do thisby basifying slowly with aqu. ammonia
and checking the precipitates with a microscope, the two alkaloids come out of solution at different rates first one as needles then the other as plates or versa vica (I can't remember which was which but I can look this up if you'd really like to know.)