How quick is it to get 100 shards for Farmboy Luke?

Have to do three refreshes, use the bonus energy and the 120 you get naturally you to do 65 sims a day, provided you don't get terrible RNG and get the 1:3 droprate you'll get around 22 shards a day from cantina.

Not guaranteed though and you are set to run out of crystals after 3 days may be 4 depending on how much you get coming in. I would consider the Luke pack as it's guaranteed shards.