2X scoring with the FUEL lane. Hit it every fifteen seconds or so when running.

2X scoring with snake during MBs. You can get it multiple times during MBs by hitting all the picks and re-locking snake. I'm not positive, but I think hitting all the picks while the ball is locked in snake resets the lock timer, 2x scoring, back to twenty seconds.

Seek and Destroy, if you can get it running, can be extended pretty easily and is worth the effort to shoot for. To reset the timer you just have to hit one of the major shots, loop, ramp or grave, and you are back to twenty seconds. Keep it running while you progress towards MBs. My personal best SND was a little over 100M.

What's great about Met is that you can get pretty much everything running at the same time. Running Seek and Destroy during coffin MB stacked with Sparky MB at 4x scoring and FUEL is sort of like a wizard mode. I'm chasing after a 586M high score on an LE and think I can get it, I've been close a few times.