Isolation solution for curved bottom floor standers?

Maybe check with a KEF dealer. Looks like the XQ30 has a similar cabinet base with outriggers on the backside for more stability. If you’re looking for isolation maybe make some maple plinths and use the Gaia’s. On the plinths you’ll just need bolt inserts for the feet. Would be fairly easy to build. Check into Mapleshade for ideas. Will raise the tweeter 3-4” higher so it might change things more than you think, or you could recess the feet into the plinth a little too.

https://shop.mapleshadestore.com/Speaker-Plinths_c_66.html

Townshend Podiums. Call John Hannant. Tell him I sent you. If Podiums won't work (should, but you never know) then ask about Pods. They are threaded on top so you may be able to screw them directly in place of existing spikes or whatever footers are on there.

Thanks guys. Those articulating feet look nice but I’m not sure they provide a whole lot of isolation do they?

Also what about me just kidding some thick slabs of wood and putting isoacoustic isolators under them and setting the speaker on top?

Once you have articulating feet you can add whatever you want under them.

Thanks guys. Those articulating feet look nice but I’m not sure they provide a whole lot of isolation do they?

None. That's meant as a joke. Well okay maybe not meant, but is anyway. Seriously. Constantly amazed the lack of .... nevermind. 

Townshend Pods or Podiums are the most effective you can do. Put speakers right on them, turn knobs to level, done. Expensive but worth every penny in sound quality.  

If instead of good you want cheap, Nobsound springs are cheap and yet better than anything else but Townshend. 

Articulating feet. "Look nice". Good one.