I've finished most of the graphics for the battle screen (not all are present, though. IE numbers, menu choices, etc.)
I planned on using the base algorithms that RM2K3 has. I'll list the one's used here:
The attacking character is designated as A, and the defending character (the one being attacked) is designated as B.
Normal Attack Damage
Damage (HP decrease value) = (Attack power of A / 2) - (Defense power of B / 4)
Normal Attack Hit Ratio
Hit ratio (%) = 100 - (100 - hit ratio % of A's equipped weapon) * (1 + (agility of B / agility of A - 1) / 2)
Skill Damage
Damage = Base Damage + (Attack power of A / 20 * Attack influence of skill) + (Defense of B / 40 * Intelligence Influence of skill)
Escape Success Ratio
Escape success (%) = (1.5 * (Average agility of party / average agility of monster group) * 100
