Here's another Youtube video of a guy (Btuff) using two shapers -- best wave he's ever had, and he experiments a ton.
https://www.youtube.com/watch?v=7eGx74kXE-E
2008 Mobius LSV
1100's each rear
490 ski locker
750 IBS
Plus bags 625 and lead 650
Reversible pumps-3
ACME 2937 prop
Fresh Air Exhaust
Swell shaper