Sedona MX 907HP is what I'm running for a 2nd time around . It's great from deep ruts to hard pack. I did 1/2 the 2017 gncc on 1 and it always found traction. It is a stuffer tire so I only run it at 8psi. (185 lb rider) I'm going back to it again for this year's hare scrambles. It wears very well too.
https://slavensracing.com/shop/mx907...-tires-sedona/
The 525 is an awesome tire if you are going to be in a mix of rocky stuff and trails. I've use it for hard endures b4. (Tough like rorr) you can tractor through the rocks. It just sticks to them. And still enough bite for mud and dirt.
It will wear the edges out rather quickly. So 8 save it for races I know are full of Boulder fields and what not.
First time running the fatty uo front, but seems to have awesome traction. Also can be ran at alittle lower psi.