We are from Sprimont - RC Electro Liege, we already had a track on clay but on some parts we were missing grip so we added some carpet/astro too, but then it's not as nice as to have a full clay track
Still I guess this possibility will have to be taken in account if we don't find anything else.
We could eventually manage to visit your track but it's a bit far away!
I'll let you know when ours is ready again.
PS : If everyone else has an idea I'm still willing to hear it