I don't know what would be "ideal" in terms of the percentage of alcohol to cut lanolin, but any reasonable cutting down of the alcohol down with water won't significantly affect the ability of the drying, except maybe to take slightly longer for everything to evaporate.
Alcohol bonds will carry a LOT of water away with it as it evaporates...you won't have any problem at all with, say, the alcohol evaporating and leaving behind water.
You can buy isopropyl alcohol at any Walmart which is 91% alcohol. You can also buy 70% there. Likely, for your purpose, either will do.
But for a buck and a half a bottle, it would be dirt cheap to buy either and do a little experimenting on your own to see what would work.
Just be aware, however, that alcohol is a powerful desiccant that will not only remove the water from your skin, it will also remove the oils. It's very damaging to the skin, especially for routine or concentrated use, so use nitrile gloves when handling it.