use high quality alcohol to extract.

Like 150 proof and higher?

you will be tasting the alcohol so good quality is preferred. high proof alcohol can damage the underside of your tongue over time and it stings so you can dilute if you like or do like me and just make oil tincture. i use canola oil and place drops under my tongue. at any rate whichever you choose the online documentation is fairly thorough.

it is actually my favorite.

I mean, would you drink it? I use vodka made from potatoes without chemicals. Leave it to extract longer for higher concentrations of the herb. Shake occasionally, leave in a dark space and break it open in a couple of months. If you keep opening it, vapors will float away with the essence of your herb. Patience and quality are key.

I would be using 4 ml of tincture.

Get a Magical Butter Machine.

I used 8 oz. of high quality shake in a fifth of Tito's vodka. I put it in a dark closet and let it sit for 60 days. Most of the vodka had been absorbed so I added more vodka. After another 30 days ( total 90 days) It was perfect! It came out looking like tar but it is wonderful. I use it for all my aches and pains which I have none of as long as I use it. Good luck!