I've built a simple 3-stage rocket with no intended crossfeed. Playing with new slanted nose cones, I've hooked them onto radial decouplers (it feels like they are made for each other, and separation in flight is perfect) And the result was that my boosters drained core tanks dry. Both nose cones and decouplers have fuel crossfeed, and placing booster fuel tank in stack under the nose cone triggered 'reverse' asparagus. ...seems like a good reason for me to learn Module Manager syntax...