Fuel Lines borked?

I tried a few staged rockets, but not being able to tell how much fuel is in any actual tanks made the results... confusing.

I tried a few more attempts using only the vague dV readings next to staging, but even that doesn't seem to work.

My only remaining suspicion is that either the fuel lines are broken, or I'm using them wrong. There were a few attempts where the lines disappeared and had to be re-attached. Made special note that the dang arrows point the right way, and that the decouplers are set to not crossfeed. The fuel makes it from the 1st stage to the 5th just fine, but the fuel seems to be used in the wrong order if at all.

Edit: Resource manager does show individual tanks. Haven't tried transferring manually yet.