Be sure you use parts and not volume if it is 2 parts comfey and 3 parts hopes for example use 2 cups of comfrey and 3 cups of hops and not 2 oz of comfrey and 3 oz of hops.
If the herbs are very resinous use 00 proof if you can gt it but for most if you cannot get 100 proof 80 proof vodka form grains is fine --the cheapest is also fine.
I save up to 90% of the cost over buying and they can last up to 10 year sand more according to Schulze while died herbs about a year so if you want to make a lot like buy lbs instead of oz of herbs, you know it will last and be good years later.
Although it can still work with conventional herbs for best results use only organic or wildcrafted herbs as these contain 7 to 10 times more of the phytochemicals that prevent and cure disease