Thank you very much! 😉
If I were you, I would try to sell low-priced cards (common/rare) in a package (you can do it @ PeakMonsters). For more valuable cards (e.g. epic/legendary) I would try to sell them individually at the right time 😁. I think this feature can help with finding it.
E.g. I have many watchlist items for hunting the best price for my legendary Chaos reward cards: