I run Vittoria XG Pro w Michelin latex tubes... If I go lower then 55 psi, I am pretty much on the rim when I do small jumps or hit roots. I am tall, powerfull and around 182lbs.

Putting in Stans tape will be moore then a Michelin tube and I will still hit the rim.. I will get Challenge Grifo´s soon and might try em tubeless on my Ksyrium Elite wheels....

I have been trying tubeless for ages but its pretty damn hard (unlike MTB tubeless which is a doddle). I havent used tubulars yet.

I havent used tubeless tyres I just use michelin mud 2s

A few points if people havent already pointed them out:

Tubeless tyres (based on the standard set-ups available) will never be as good as tubular.
There are a number of ways a tubeless tyre can fail, espeically over a period of time, with tubulars there is really only a couple: puncture (but you can put sealant in tubular tyres to stop this), rolling off and pinch flat
Pinch flatting a tubular is much harder due to the shape of the rim.

There is much greater leverage on a cyclocross tubeless tyre compared to an XC tyre so the tyre needs to have an extremely tight/secure fit on the rim. The sealing of the tyre must be absolutely fool proof and tested, dont just rely on 'its tubeless ready' label.

Once the tyre is fitted put 5psi in and squash the bead as far into the centre of the rim as possible. If it hisses its not going to work when raced hard. You cannot rely on the air pressure inside the tyre to keep the tyre sealed (unless you are running the maximum pressure possible which defeats the point of tubeless). This is because if you get the slightest air-loss, the tyre can drop from 30-25psi, in just one hiss, once its at 25psi, it makes it very easy to hiss again.

Check the tyre again after a week to see if the tyre has stretched or the rim tape has moved.

All in all expect to waste a fair amount of time faffing around, and also to reguarly check your tyres/ rim tape equipment for wear/leaks.

My most succesful set up so far has been the newest version of maxxis larsen tyres. Although they really are trail riding tyres not racing tyres (they are officially 35mm although they are actually 32mm when measured).