Heard shellac takes 24 hr to dissolve in methylated spirits?

It would depend on how much you mixed. Pre-mixed shellac uses three pounds of flakes to a gallon of alcohol. You would use less than that for a better finish because several thin layers work better than a single thick layer.

You say methanol, the page at en.wikipedia.org/wiki/Shellac says ethanol. That might have something to do with it. It is best to get all your advice from the paint store.