If you're aiming for max damage, no matter the difficulty, you can get 627 for 2 bars starting from midscreen. Also the SDM Orochinagi seems to do 5 more damage (and comes out faster) than the other SDM for the same amount of charge time.
jp d C, CD xx hcb B (whiff), D xx BC, D xx rdp BD, qcf B xx K, qcf AC, qcf A xx qcf A xx SDM (charge)
I could be wrong about the last part since I'm typing from memory.
jp d C, CD xx hcb B (whiff), D xx BC, D xx rdp BD, qcf B xx K, qcf AC, qcf A xx qcf A xx SDM (charge)
I could be wrong about the last part since I'm typing from memory.