Just a note in the X-formula/Dragon tech vs Spit (and what it means for indoor surfaces)
The Powell bones stuff comes from the downhill program, designing soft wheels that slide. From what I understand way Powell did it was to engineer a wheel that was softer but not so damp.
Harder wheels do this naturally, that’s the screech. But it’s not enough grip or absorbtion on rough ground.
The Dragon/X are specifically designed to vibrate on rough surfaces when slid, so it’s more the tiny vibrations letting them glide over rough surfaces rather than the quality of the urethane being ground down (which is what I think how softer slide wheels were designed, to wear down and eventually come and flat spot)
So they are designed pretty much just for rough surfaces. If the surface is too flat and perfect (like a skatepark), they just grip and there’s too much surface sticking to start a good vibration and slide. That’s how it feels to me at least when I take them in the park.
So in that case, they would probably be good for an indoor park.
As for the newer softer spits, I really don’t know how they are sliding, by vibration, breaking down, or what combination of both.
I had the first iteration of 97 spits when they came out, and hated them. They just felt gummy and damp, like a regular 97a.
I haven’t tried the new formula, but let me know if you think they are a vibrating wheel or a wheel that wears down.