Certainly for a good long portion of the race (6-8 hours before considering it, and then only if you really, really want to).
I do a lot of not running in six hour races and do alright, so I can only imagine in 12 there's an even larger opportunity for measured pace.
In theory I know it is not smart to run because I cannot run for 12 hours, and it will only tire myself out. But I tend to get excited and take off, even though I know its not smart. I'm hoping between the hills and my knee not being 100% I'll be able to stay grounded.
Channel your inner mellow Matthew McConaughey ("alright alright alright"). Enjoy how others will do all the heavy lifting to your first and second point while you are busy studying scale, woods runnability, steepness, whether spurs or gullies have the best travel or visibility, do gullies have water that's not on the map, do gullies with water on the map have water for real, etc. Take notes on time to climb versus flat line speed, so you can use it to inform later routes (when you really need to know if 3x farther is better or worse than one more 200' hill climb!).
Always better than throwing down 7:30 pace one minute into a race where the average speed is no better than 20:00/mile for the top 5-10%.