To answer a few of your questions--I think simmering would be a safer bet, though I've always boiled during my extractions and haven't had any problems.
I recommend shaking the naptha around, but not for 5 minutes. It's true you don't want it to heat up at all and you want to filter ASAP. I usually a quick but hardy shake for a few seconds, then quickly pour off the naptha.
I get a nice fluffy white product in the end with Marsofold's tek. If that's the case with you I wouldn't bother with a wash, but if you want to stay on the safe side than the sodium carbonate wash is definitely your best bet. An ammonia wash will waste a lot of your spice.
Hope this was helpful. As for your question regarding ratios, I'd think you should just have to do some conversions and scale the ratio down--but I'll leave that one up to someone more knowledgeable than me.
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