After a bone is watered once, bones planted after it in that same spot do not need to be watered. This saves time and piss. I discovered this after noticing some strange behaviors in bone farming such as not needing 25p to water bones and bones growing watered despite not being watered. I consider this an oversight.
I agree that the city ruins jump seems too risky for the amount of time it saves. I didn't know that jump could be made though. I figured out those jumps in the citadel in my last run. I look down at the ground and jump when my cursor lines up with a vertex. The jump at the top is like, the one place where getting stuck is a good thing. The jump in the burg mart is a really good shortcut, I don't know why I didn't see that.
Yobby and I have a discord server for Crypt World speedrunners. If you're interested, here is the link: