Ive done 2 cx races this year on a diy tubeless setup. My setup is far from ideal but proves it does work ok if you are prepaired to try things out.
Wheels = planet x model B road wheels, narrow, a bit rubish and cheap, a few wrapps of tape needed to get build up the rim first.
Tyres = Michelin mud2, not the greatest at any one thing other than going tubeless, they grip the bead well and dont loose air. Can get overwhelmed in the mud, not the greatest mud tyre.
Not sure on exact preasure but around 37 psi according to the track pump at 80kg.
below 30 and its squirmtastic but didnt burp, just collapsed.
I think the whole setup would work better with a wider internal width and tubeless rims, like crests/ironcross