So a few weeks ago, I did the DT Fate farm, and all of them died fairly fast, even if I had 2-3 others in my party during early morning and mid-day times. Also, I actually dislike fates, so I never do them, so I don't have a shared fate, so I just traded extra bi-colors into lamps, which I discarded later. The main reason I did them was because I knew certain colors were in odd zones that rarely had CE and DT fates would 100% give me the right color, even if it was boring.

FWIW: I feel like you're still going to waste time either way in OC (dupes) vs DT Fates (boring) since there's no way you can make progress in the quest w/o collecting all the atma. For example, nothing is stopping me from returning to OC now that I've almost done all the relics from tome dailies, and I can still make progress on PT jobs.