You can't set it to a percentage, I'm afraid. And that's the max blood setting... I think it's bloody enough.
Units don't pile up, it's just one layer.
Btw can you tell us what excat numbers and units were in the gobling/ogre army and the elven army, just want to check if it was even and what best to use against the other types
I don't have any of that saved or recorded, but I'll set up a new scenario for you.
I started by placing the following units on a blank regional map in the scenario editor:
10 Battalions of Raiders (150 Units)
8 Battalions of Prowlers (120 Units)
5 Battalions of Wargs (25 Units)
Total: 303 Units
6 Battalions of Sentries (42 Units)
6 Battalions of Rangers (42 Units)
2 Battalions of Grand Masters (14 Units)
3 Battalions of Bladestorms (21 Units)
1 Battalion of Mounted Grand Masters (5 Units)
2 Battalions of Unicorns (10 Units)
Total: 134 Units
In the above screenshot, the orcs are represented by the blue battalion markers, and red is used for the elves. Both sides had a similar layout with a semicircle of archers in the back, various infantry units up front, and the heaviest concentration of mounts off to the sides.
All units started off as level ones with no upgrades.
As soon as the battle started, all the melee units attacked eachother, concentrating in the center of the battle field. During this time, the archers fired a steady stream of arrows into the crowd. When the melee fighting was over, all that remained were two ogres and a couple wargs. These remaining units charged out at the elven rangers, but were quickly shot down in a volley of arrows from every side. I moved my goblin archers in a little as they have horrible range (the only interaction I had in the battle), and the battle came down to my prowlers and the opposing rangers. My melee units had taken out a good chunk of their archers, and I was down a couple battalions but still greatly outnumbered them. However, as I broke through the heavy armor of each ranger, my remaining goblins fell like dominoes.
In the end, however, I won the battle with 18 level four and 30 level three goblin prowlers - many of whom only had a sliver of health.
Now if you're looking at the number of casualties alone, don't lose faith in the orcs. Keep in mind that the elves and orcs are on opposite ends of the spectrum. The elven units are typically the strongest units in the game, especially their archers, while orc archers suck. However, they are also very expensive. The orc units are the weakest on average, but they have the largest populations and many of their warriors and work force don't cost players a dime after they build the necessary buildings.
Also, my casualties would have been significantly lower if I took a direct role in this battle instead of leaving it up to the AI. I would have taken some of my wargs, and charged through the ranks of elven rangers and I would have spent all the skill points I accumulated, making the rest of the game a breeze. The elves would have a couple advantages played by humans too, but they don't have as many units to spare from the main battle to target the archers.