This is the best race in the world mate, honestly do it. Go up the day before with a map and a compass (you won't have to use them if it's clear) and check out the route. It's straight up Lingmell then along to the summit. I've done it three times and I've never gone wrong yet...I've done it in the clag and managed to find the right line just by sense, memory and following people but you could definitely get lost a bit on the descent. It should only take 2.5 or 3 hours to walk up and down easily.