If you don't have Faris call, you can try Seymour or Caius calls.
0:00 Overview of L and R Gates
5:06 Reckoning stage start
Reset until turn order is Wakka, Kam'lanaut and Machina
Wakka uses Faris LDCA and then Status Reels
Kam'lanaut uses Kurasame base call, and uses LD IF boss only has 6 debuffs. If boss is at 7 debuffs, use EX instead
Machina uses LD and this should complete your Debuffing setup. From here, if Wakka's next turn is after boss, use Raines base call to pull him back. Have Wakka refresh his call debuffs.
Make sure boss is at Action Reels before going summon mode, you can try to trigger this by using Wakka LD
Use Machina BT+ and Kurasame LDCA before going Summon Mode
10:08 Summon Mode
Have Machina use Raines LDCA before popping his BT mode