Soak? I'm not sure how other people do it, but soaking isnt something I would want to do.
I personally put my alcohol and flower separately in the deep freeze making sure it's as cold as I can get it, then I put them in a bucket and mix it hard and fast. No more than like a minute. Then strain it out through a colander, after that I filter it out with a 20 micron filter. AkA coffee filters.
Then it gets poured in to a large pyrex glass casserole dish, put inside a box with a computer fan exhausting till it evaporates.
I find the longer the cannabis stays in contact with the alcohol, the more chlorophyll you get. Making your concentrate dark.