With the oil it varies....the thinnest layers are dry to the touch in about 3 days. White takes a little longer since it's safflower or sunflower seed oil based. Thicker layers are weeks to months. So I give the thin layered one about a month before varnishing and the others at least 6 mos. But...with the wax there's no need to varnish.
And yeah, you have to heat in a double boiler. It's a pure beeswax so it takes alot of heat and cools nearly instantly as soon as you put it down. So it goes down one brush stroke at a time, which with larger pieces can take all day. Then you have to set the wax and smooth it with a hair dryer or heat gun. Then it's like painting and that takes as long as it takes. All of that happens before any paint goes down...so it's pretty time consuming....