Also worth noting that the decent/pro riders have little problems with the mud it seems to me so the answer is to keep your speed and momentum up and shed the mud. Easy !
I’m far from being a pro (or in any way half decent), but I think you’ll gain more elsewhere on a lap running dry(er) condition tyres than you will running full mud tyres. There’s perhaps 20-30% of the course where you’d benefit from Mud tyres, the rest of it is hard enough that whatever the weather, you can ride on almost any tyre.
Don’t get me wrong, it’ll be a slippy nightmare in the mud on dry(er) tyres, but as long as they’re thin enough they don’t clog your bike (will be taking a rigid fork for my HT too and assessing on the day) I think full on mud tyres won’t really be worthwhile.
If it rains every day from now until mayhem, and rains all weekend of the race though, mud tyres will be the order of the day.
As for the 29er boys thinking about CX tyres… Probably not a bad idea if you’re prepared for the pounding over the rough terrain. Speed + mud shedding ability are the desired factors here I think. I’m tempted to blag a 29er off someone for the race for that reason and sling some CX tyres on it!