Random Spellcast for Weapons

It is set here, you just have to modify the value of the CMP instruction:

Code:

C2/3649: AD 89 3A     LDA $3A89
C2/364C: 89 40        BIT #$40   (is "cast randomly with fight" bit set in the
                                  weapon spellcast byte?)
C2/364E: F0 15        BEQ $3665  (if not, Exit function)
C2/3650: EB           XBA
C2/3651: 20 5A 4B     JSR $4B5A  (random #, 0 to 255)
C2/3654: C9 40        CMP #$40
C2/3656: B0 0D        BCS $3665  (if that # is 64 or greater, exit function.  iow, exit
                                  3/4 of time.)