You said after doing a polar/non polar extraction of HBW seeds that you're left with "pure LSA" and I'm not sure what you mean by "LSA". There isn't just one alkaloid in HBW that produces the psychoactive effects but rather a group of alkaloids called "LSA's" (Lysergic acid amides). I assume by the term "LSA" you are referring to an alkaloid in HBW/MG/Rivea called Ergine. If this is what you're referring to actually research on ingesting pure Ergine indicates it actually has bland, boring sedative effects when taken on its own. Read what Shulgin and Hoffman have to say about Ergine.
I'm weary of extracting HBW/MG seeds in a solvent or water as I assume not every alkaloid will be soluble in the extraction. And I want to put in my body the full mixture of alkaloids as I think it's the synergy which produces such an interesting, deep trip. Offhand, I recall that some of the other alkaloids in HBW are: Isoergine, Ergonovine and Methylergonovine and I'm sure there's plenty more I forgot to mention. I'd love to know which alkaloids are responsible for the nausea and muscle cramps.
Yeah, diff. batches of HBW from diff. vendors can vary tremendously. One vendor's seeds may be stronger, more visual, more stimulating, more insightful, less nausea inducing, less muscle cramp inducing, and more stoning than another vendor's seeds. I prefer HBW seeds that give me a very clean stimulating/trippy feeling (almost MDxx or Psilocybin esque) free of nausea and body cramps to some batches which give me more of a sleepy, heavy, sluggish, stoned feeling (MJ/Opiate esque) with nausea and cramps.
I also agree with you about batch varietys. Most i've got have had slightly different effects. The strength of each batch can vary considerably too.
You're smart to crush your seeds up finely and the finer you grind them the better your body will be able to absorb the LSA's. I use the biggest sized capsules I can find and it usually takes me at least 4 or 5 capsules to fit all my crushed HBW. I'd recommend you try to wait longer than 30 mins. to vomit though. Give your body at least an hour or 2 to absorb the LSA's before vomiting. Vomiting too soon can decrease the intensity and duration of the trip.
Once you feel like a real HBW/MG veteran try preloading on a high dose of Piracetam (2-4 grams) and/or Hydergine before your HBW trip. If you want a truly balls to the wall trip preload on an MAOI too. 3-4 grams of ground Syrian Rue will give your body enough MAO inhibition to make the HBW trip MUCH more physically and mentally intense, euphoric. and long lasting. I warn you though that Rue tastes horrible, can cause nausea itself and can make one feel sleepy and heavy.
The prescription MAOI, Moclobemide, may be a better choice as an MAOI potentiator of HBW/MG. So far, I've never read of anyone online using Moclobemide as a booster to HBW/MG. I can only find stories of folks using Moclobemide to boost Psilocybin or DMT.