The coggan CTL model stops working in ultra stuff really, after a few days. Given all I can do is 150w and my ftp would be like 200w. But it's the best there is. But take all number with a pinch of salt, they don't even begin to tell the story really!
FTP doesn't mean shit when you're spending 11hrs in a lodge waiting for your ankles to move again or running into service stations every 2hrs to put fresh cream on your arse :)
just read @skinny 's TCR interview on Evans, -115 TSB!!
I just had a look, my CTL is reasonable (75) yet ive never had a TSB higher than -10, thats absolutely insane