Now, as I promised, I've gone back to building levels
Cry for me: reducing the climbers to 40 should be enough to remove the backroute.
Circular Ruins: removed a backroute. Clam's solution still works, but the steel will no longer stop the last digger in the right place, so the batter must be used. This means both solutions use the same skills (everything but the runner).
You have to build: modified terrain to match Circular Ruins.
Leap of Faith: This is Level 9 of Ben Bryant's Cheapo set "sg1". The whole set is excellent and I could happily remake them all, but there are still too many of my own levels I want to do
So, I may occasionally take a break from my levels and do another from this set.