GTD - I've looked back at the results for 2012, but it's far too complicated for me to figure out average (decreasing) pace! I did plan on a 25/5 run/walk strategy, but that went out of the window as soon as we set off. I was far too excited. There's another lesson for this year!
This year I'll probably go with trying to sustain a decent average pace for as long as I can, then death-march if needs be. All about the strategic prep, me. So, you've entered then?
Not sure how qualified I am to give advice - you've done more marathons than I have, and Comrades isn't easy is it? I guess 4x back to back marathons is probably good prep - which it seems neither me or T rex have been doing!
Is the quad lumpy or flat? I seem to have been gravitating towards hills recently, which is probably pretty rubbish for a pan-flat ton. I've been thinking about this for a good prep race; http://www.cannonballevents.co.uk/canalathon.php as it mirrors the terrain pretty well. If you're Northern enough, or don't mind getting your passport out, it could be a good insight (it's Manchester-Rochdale).
FWIW I was in this in 2012 and DNF'd at Reading. I was a bit too green then, and got it all wrong pace-wise; started off conservative and slowed down so much when I got tired (sleepy tired, not exhausted tired) that I could almost smell the sweepers behind me!
So yes, if you think it's a good idea - go for it. It's an interesting enough course (perhaps more so when South of Birmingham is a mystery), and Centurian run their events very well.
Did this last year, and if I was able I'd be in for the double without question this year. Unfortunately it's not possible due to a clash with other commitments, but for anyone considering it I'd highly recommend it. It's a tough trail marathon, but that's what you want, right? Priddy, challenging, well run and cheap as chips. Why wouldn't you?
brer/T rex - re the Ro'F; sounds like Newborough forest to me. A couple of folk got lost and spent the night in 2012 (one of whom I know is going back this year to get revenge!). It can be a bit disorienting in there at night - tracks everywhere, but they did put a few glowsticks out last year. There's a section through fields after Newborough, to get to Aberffraw, which is also a bit of an arse - I managed to tag on to some local lads last year, which helped. Definitely worth a recce if you can. That last stretch of day 2 along the beach towards Aberfffraw makes it all worthwhile though...