Visca 0 Newbie Poster

I'm working on a final project for school and I have a problem with the number of databases.

I only have a month for this project, and the teachers made a change on it (to see how we can adapt to an started project. On real world most of the work we go to do is develop an started project) and only three weeks left.

Initially we must make a win32 application to administrate a web. Now we have to do a win32 application to administrate similars webs. I have to decide about make only one database for multiple webs or multiple databases. We discussed (we are a team of 5 students) why do one or other option.

PROS for single database:
Less space used in disk (there are a few data equals for all the webs, two tables of 15). The teacher says it's more optimal.

CONS for single database:
We must to add a new table ("projects") to control the shown data on each web.
We must to do a few relation tables betwen the "projects" and the existing ones.
The "select"s will increase a lot (like 2 or 3 tables and 3 or 4 conditions to control this. I supose it will take more time to make selects, and then, what you win in space (see PROS of single database) you lose in time.
The time to implement.

PROS for multiple database:
Better performance for security (the rights will work for tables and projects, not the same rights on all projects).
Quicker implementation (is already implemented!).
Democratically win (3 vs 1, win for multiple databases option), but we have to say in documentation why we choose this decision.
We have 5 teacher, 1 thinks this is a good option, 1 thinks the other option is better but this is acceptable, the other 3 don't says anything. Changing to single database will take more time than the punctuation we can earn doing it.

CONS for multiple database:
1 teacher says the single database is a better option and this is an important point, this teacher is the responsible of teach databases at class, it's only an important point for him, the other teachers will ignore this decision.

Also, you might think it's already decided (democratically), and you have nothing to do with this. But anybody of us are secure about this decision. Help us! (We will write in documentation your help as a consultant, so please, give me your name/nick/alias and the price for your help, and your experience (is the guarantee for your response), you will appear on credits XD, but I'm not going to pay!!)

Sorry for my bad English and thanks for your help and time!.