I’ve done the single’s a few times over winter, last year I did 2 one in Jan and one in Feb.
I tried to choose a decent day for it by tracking the weather but was unable to find dry/cold days, both rides were in the end misty muddy affairs.
The stint from Winny to QECP wasn’t too bad as there are a lot of open exposed areas, the wooded bits and valley drop sections were a mud spattered fest. Onwards from QECP to Amberly were fine, again when you are under the trees it’s gloopy but once on the tops it was the normal slippy clay/chalk, as you would expect. Properly slippy in the off camber rooted sections and field run off segments. Thats all you’ve got to worry about I reckon. Most of the sections on the tops were not dry but they weren’t gloopy just soggy.
I think it’s doable, go prepared for a longer time and more effort, feed up and drink well and dress for the occasion and it’s a go’er.
Also, well it gets really dank and misty up there if you are unlucky, both times I had sections of dank mist and that made for some interesting blasts.
I did it on my CX’er with no bother.