Right. Since nobody is telling me the offsets for the boss HPs, I've figured it out for myself.
Monster X: 0x047E813______________________________MOV DWORD PTR DS:[ECX+40],2BC
Balfrog: 0x04793E4________________________________MOV DWORD PTR DS:[ECX+40],12C
Core: 0x04744CD__________________________________MOV DWORD PTR DS:[ECX+40],28A
Ironhead: 0x047AA4B______________________________MOV DWORD PTR DS:[ECX+40],190
Sisters: 0x047D2EE________________________________MOV DWORD PTR DS:[ECX+40],1F4
Undead Core: 0x04754C0____________________________MOV DWORD PTR DS:[ECX+40],2BC
Heavy Press: 0x047C985_____________________________MOV DWORD PTR DS:[ECX+40],2BC
Ballos 2nd Form: 0x04774C4_________________________MOV DWORD PTR DS:[ECX+40],320
Ballos 4th Form: 0x0477AE6_________________________MOV DWORD PTR DS:[ECX+40],4B0