I think the Jazz should have them work out against one another. Otherwise, I think Paul Reed has more potential. He's the better and more versatile defender, meaning he could play next to Gobert and play multiple positions. He also has better ball skills for a system that shares the ball and uses passing, cutting and multiple pick-and-rolls.
That said, I think the Jazz should offer #24 + Royce to move up to the mid-teens--either Minnesota at #16 or Orlando at #15. Then the Jazz could take Pokusevski or Saddiq Bey. Royce is mostly a designated defender who has very low usage on offense. The Jazz might be able to replace that with Miye Oni off the bench next season. It might be worth making this move to get someone with more upside in the draft. Royce is on a fair extension for the next 3 years, and in a draft that's pretty flat outside the top 10, a team might go for Royce + 24 to shore up two positions instead of one.
If the Jazz stay at #24, I think Reed is a real possibility, assuming he doesn't bomb his interview and the Jazz think they can help his shooting.