Hogwarts School of Witchcraft and Wizardry is transplanted across the field from Helm's Deep via an Alien Space Bat. This translates to the school having their whole grounds basically, while Helm's Deep is across from them for the whole length of field. Both of them have the goal of eliminating the other side basically but can play it smart/stay behind fortress walls as they like to achieve that goal.
Helm's Deep side will not be affected by the general misdirection spell I think the school has.
1) Helm's Deep has the reinforcements from Gandalf arriving etc
2) Helm's Deep has the 10,000 Uruk-Hai now on their side to help them.
3) Helm's Deep has the Uruk-Hai and Ents to help them. Hogwarts has their whole population of magical creatures as shown in the work and also Voldemort+Death Eaters.
Numbers vs versatility, which side takes it?