http://recipebook.bentasker.i2p/categories/isopropyl.html
The measures below will create about 60ml (give or take depending on the essential oil), you should increase proportionally if you need more - to be effective the alcohol content must be at least 60%, the measures given will create a 64% concentration (assuming your total essential oil addition weighs in at 1ml, which is perhaps over generous). You need 99.9% Isopropyl for this, using 70% won't work as you'll water it down below that important 60% mark. You can, however, dehydrate...