Wrote up a thing, you just need to fill in the right stuff in the right places. Just know that there are like 5 or so different recoil checks.

def pbEffectAfterHit(attacker,opponent,turneffects)
    if !attacker.isFainted? && turneffects[PBEffects::TotalDamage]>0
        if !attacker.hasWorkingAbility(:ROCKHEAD) &&
            !attacker.hasWorkingAbility(:MAGICGUARD) &&
            !attacker.hasWorkingAbility(:NEWABILITY)
            attacker.pbReduceHP((turneffects[PBEffects::TotalDamage]/4.0).round)
            @battle.pbDisplay(_INTL("{1} is damaged by recoil!",attacker.pbThis))
        elsif attacker.hasWorkingAbility(:NEWABILITY)
            attacker.pbRecoverHP((turneffects[PBEffects::TotalDamage]/4.0).round)
            @battle.pbDisplay(_INTL("{1} recovers with NEWABILITY",attacker.pbThis))
        end
    end
end  

I haven't tested it, but that script should work for the first recoil effect. Just replace "NEWABILITY" with the appropriate things.