The reason for this is that these RC papers are still designed to work with
stabilization processors where the image has to be fully developed in about
3 seconds or so. Many people have reported good carbro results with the N
surface RC papers over the years. Just make sure you don't use a hardener
with the fix and perhaps Sandy can say a word or two about the type of
developer he uses, as the regular ones tend to harden the gelatin somewhat.
As for oil or bromoil, the transfer technique is definitely the way to go
indeed. The image loses this unpleasant (to me) shinyness, and less oil
ends up on the final print. Oil in oil based prints is undesirable for
conservation reasons. There is currently a discussion in progress on this
very topic in the Prints-L list.
Luis Nadeau