Changing physical damage calculations?

Wow, thank you, Madsuir. I believe this may be exactly what I'm looking for. I'm going to give this a shot soon enough, and try to see what works best.

On an unrelated note, I've also been considering replacing the Soul Sabre effect with an effect similar to that of the Tempest's effect, only using a different spell in Tempest's place. The idea is to have another weapon randomly cast Magnitude8, while keeping the Tempest and its ability to cast Wind Slash. The Soul Sabre effect, as per the disassembly, has 16 bytes of data, while the Tempest ability has 14 bytes, and I am wondering if this is possible without doing a whole lot of rearranging.

Code:

Special Effect 6 - Soul Sabre

C2/3F6E: A9 80        LDA #$80    
C2/3F70: 0C A3 11     TSB $11A3   (Sets attack to Concern MP)
C2/3F73: A9 08        LDA #$08    (Special Effect 5 - Drainer jumps here)
C2/3F75: 0C A2 11     TSB $11A2   (Sets attack to heal undead)
C2/3F78: A9 02        LDA #$02
C2/3F7A: 0C A4 11     TSB $11A4   (Sets attack to redirection)
C2/3F7D: 60           RTS

Code:

(Wind Slash - Tempest)

C2/3F9F: 20 5A 4B     JSR $4B5A   (Random Number Function: 0 to 255)
C2/3FA2: C9 80        CMP #$80
C2/3FA4: B0 10        BCS $3FB6   (50% chance exit function)
C2/3FA6: 9C A6 11     STZ $11A6   (Clear Battle Power)
C2/3FA9: A9 65        LDA #$65    (Wind Slash spell number)
C2/3FAB: 80 03        BRA $3FB0