Very useful CK, thanks. Agreed about the organisation, last year's event was great.
Annandale Water was my sleep control last year - it's about the same distance this year. I arrived with more than 5h in hand; this was my plan but it was more by luck than judgement that I achieved it, having sat in for the first 50km at 30kph.
Last year was veh flat for the first 150km or so, then hilly up Wensleydale and across to Penrith, then flat again from Penrith up to Annandale Water (and stayed relatively flat all the way til Galashiels really). From Galashiels to the finish was hilly.
This year, going to Longtown Newcastleton Kelso early on will probably make the first section slower. So I would delay the sleep stop to allow making up time on the flat bits that come later
on, maybe. Mr Series' suggestion sounds like a good 'un.