That can be and is debatable.
I like building minor gordo`s and it takes an extremely large amount of Pink Orbs. I find the best dig time to be mixed digs at 4:30PM server time. I actually get just as many Rare artie`s along with several uncommon, followed by the commons. Use 9 turns and you will get at least 1 rare every 4th time, two uncommons every two-2-three times, and 3-to-6 commons on every click using 9 turns. (This is with a paid account using a 3land spaz). using arties for luck will also help get more rare arties at this time too.