SJC posted:Ballast the first few inches to foot inside the portals. Why waste your time and money ballasting an area that, it appears, will be inside of a tunnel.
Again, don't waste time or money in a spot you won't see and that will be in total darkness.
Time and money - two excellent reasons to not ballast what can not be seen.
Also consider, anything that you do on your layout that you cannot see or gain ready access to will at some time in the future be the source of a problem.