There are more than one quote on the force leaving isengard in one the hobbits specifically mention half-orcs and normal humans...
I mean:
"He emptied Isengard. I saw the enemy go: endless lines of marching Orcs; and troops of them mounted on great wolves. And there were battalions of Men, too. Many of them carried torches, and in the flare I could see their faces. Most of them were ordinary men, rather tall and dark-haired, and grim but not particularly evil-looking. But there were some others that were horrible: man-high, but with goblin-faces, sallow, leering, squint-eyed. Do you know, they reminded me at once of that Southerner at Bree: only he was not so obviously orc-like as most of these were.'"
Erkenbrand of course! I must have confused them because of that damn movie!
So, given that this 10:1 ratio is Orcs vs. humans (given, probably amongst the best ever) in open combat would you say that 10:1 might not be enough for Orcs vs. Calaquendi?
You know that is hard to say and That difficulty is what i am all about.I acknowledge that the gladden orcs are probably not the elite, not the best equipped, but they have among them a number of well trained, well equipped barad-dur orcs plus they have the surprise and an evil will driving them. The numenoreans are total elite and well equipped, but also only light equipped as they are equipped to travel not to battle.
Tol sirion, other situation.the Orcs are maybe part simple war-slaves/force commited miners and workers but a large number should be well trained warriors too.we don't know the relation.they are however all extremely well equipped from the smithies of angband, commanded by demons, supported by werewolves, demons, trolls... all that is huge plus.
On the other hand:we have the elves, technically as strong ,fast and fit as the strongest humans, very well equipped by their own smiths as well as the dwarves, very well trained, everyone is a professional lehionaire/hoplite even those who are common workers/planters/craftsmen in daily life... plus they have seen the light of aman and have a strong good power supporting them, even if subtle.
So: hard to say.I won't compare all three battles.