3 weeks isn't really something to worry about but since youre willing to put the effort into it by all means do it. I would keep a small container of gas around with a little bit of light oil mixed in it. Run it thru the fuel pump and carb until you see the engine begin to smoke (you might want to get a spark plug you can use for just this purpose, the next step hotter than your race plug. Drain carb, remove air cleaner and seal carb intake. Roll engine over to bottom dead center so the valve springs dont stay compressed for 3 weeks. If you drain the oil, put a reminder tag on the engine saying it needs oil.