i am currently on day 6 of my isopropyl extraction of 50g dry, hopefully it turns out as good as planned
I would think that with 50g you could probably just start soaking the powder and shaking sporadically over half-hour or so intervals, and then replacing with fresh alcohol, and probably have it turn clear after using around a quart or two of IPA. I could be wrong though.
The reason for soaking the powder in IPA for long periods of time is the assumption that the IPA is absorbing more and more goodies over that time period, and that the longer the time period for each invidual soak means more goodies per quantity of alcohol, and so less overall IPA you'll have to evaporate in the end. You could switch out your IPA every five minutes and after awhile the alcohol would start to turn clear, but the assumption is that if you did this you'd end up with a ton of alcohol to evaporate.
This rationale could be completely bogus, of course. It could be the case that at room temperature the alcohol absorbs all its going to get within minutes. I really don't know. I've just read from various internet sources that you need to let your soaks go for 24 hours or so, but I've never read this from a scientific source. I've also read on the net that you need to soak for weeks at a time, and this is obviously wrong.
A friend with some science schooling (unlike myself) said that there shouldn't be a need for the individual soaks with fresh IPA at room temperature to be longer than a couple hours at the most, and that increasing your temperature even by just 10-20 degrees should increase the absorption tremendously. He said that if you could raise your temperature a bit and rig up some contraption that would agitate your jars continuously, then the IPA ought to absorb all its going to get fairly quickly, like an hour or so.
Being pretty high we came up with the idea of using a cooler, a neck massager, duct tape, and a light bulb. I think it could work :p
IPA is so cheap, I think next time I do this I'll perform some science experiments and figure out how much time really affects absorption at room temperature.