There's another option: avoid the chemistry extractions altogether, and try it "full spectrum". That is, you put the powdered cactus directly into gelcaps (or put dried pieces into a blender to turn into powder, and then into gelcaps). 3Tblspns of such powder might be just the ticket ... but start low to see how YOU like it. (you can also just put the powder into orange juice, stir, and aim it at the back of your throat so it spends minimum time on your taste buds.)
Similar to the "jungle spice" you read about here, full spectrum cactus is often described as a richer, deeper mescaline experience. It is true that we don't have a total handle on all the chemicals in cactus that do not get extracted, but we know what many of them are. Different species, and different specimans are all going to be different from each other. But like many of us, I've sampled many Trich species full-spectrum, and while there are some subtle and some not so subtle differnces, mescaline is behind them all and it's all good!
WHOA!