>>53298661After doing the raid again it actually turns out that +3 tera grass Flower Trick on Grassy Terrain is a 4 hit KO. For even further idiot-proofing here's how my last raid went on a turn per turn basis:
T1: Knock Off
T2: Knock Off
T3: Die
T4: Flower Trick after revival
T5: Terastalize and Hone Claws
T6: Hone Claws again
T7: Grassy Terrain
T8: Hone Claws
T9: Flower Trick
T10: Flower Trick
T11: Flower Trick
T12: Flower Trick
Of course I got lucky with a Thunder + Play Rough Miss and hitting twice through paralysis but the first 5 turns should very consistent overall.