thanks - I'm feeling like a blob, hopefully that's a good thing
It's a good thing, you'll "unblob" once you get going :)
Good luck! Hope Blob means full of carbs.
I ran a 50 miler on that course in 1993. It was very run-able at the time. We did four 12.5 mile loops. I think you will do well. How far under 20 hours can you go?
Push hard and it will go easy.