Both sets are great.
They are both hybrids 43mm with a 25mm label. The best choice in my opinion here.
They both come with a dedicated dealer and a bounty which is oversized and distinct from the other chips. I like how the art of the Dunes has been adapted for the bounty with the "smoke" effect. There is just one thing that would tilt me for the HMK set : at the end of the game, only plaques might be in use which I'm not fan (just personal preference).
For a tournament set, I tend to prefer all the same spots across the entire. The progression chosen by HMK is very nice but I prefer the 8V across the whole set.
For the chip colors, I tend to prefer the HMK even both lineups are well thought.
No dirty stack and all denom clearly visible on both sets. So no minus for any set here.
For the theme, I like the simplicity and the Golden effect of HMK. The Dunes is also a great revisit (not a copy) - this makes a great tribute to the Dunes. Small détails are also there with the gradient in the denom matching the chip color. For the theme I do prefer the Dunes.
It's very tight but I give my vote for Dunes here.
Both sets are amazing and I'd be glad to have a game with both. Congrats and good luck to both of you.