Well, here's the team I'm using for monster chopper:
Captain: Lv 86 Jozu
Friend Captain: Jozu (Level 60-99)
Lv 50 DJ Sanji
Lv 63 Kaku
Lv 37 Capone
Our Lord and Savior, God Usopp.
The idea is to orb manipulate and stall (but not taking damage, or at least, too much damage) on the first 3 waves, use Sanji's special on the 4th wave, and then have 40-45K HP at the start of Monster Chopper. You will be able to survive at least 4 of chopper's regular attacks, possibly 5 with a few meat orbs. So, go to town on him, have your orbs set up. By the time he has you down to sub 10k (or ~12K) HP, your orbs should be set up (hopefully without needing to use capone's special), and he should be down to 50% HP, or maybe slightly lower
Use Usopp's special, use kaku's special, attack, use capone's special (assuming RNG gave you a few STR/DEX orbs - if not, keep it in your back pocket ) , attack, he should be dead. If not then you still have 2 turns to finish him off