I reckon a 100mm – 120mm bike is about right.
Also, I find XC Race bikes a bit too steep and stretched for both trail riding and also for endurance races. for long distance stuff, I find I want something comfy, efficient and relaxing to ride. after 6 or 7 hours in the saddle, your head gets tired, so you don’t want anything too twitchy. IMHO.
I rode the EX last couple of years, did the 2010 strathpuffer and Kielder100 on it, amongst other events. Liked it a lot. However, Last autumn I decided I wanted somthing a little faster feeling and so swapped the frame out for a SC Superlight. I’ve got that built up with the same 120mm reba Maxle forks, 70mm stem and wide, low rise bars. I’m really enjoying this for general trail riding as well as long distance stuff.
Keeping things light where you can, but stiff where it needs to be, means you get a bike that can rack up the miles as well as pin it on techy singletrack trails.