Change number for Initial load

Hello Gurus,

We are loading all our material masters, BOMs, and DIRs into SAP. We are having them change controlled. So in all we are going to have 30,000 objects or more. So will it be a good idea to have multiple change numbers created and use them for different objects or is it ok for us to use one change number to create all the objects. Also is there a way after go live we do no allow any one else to use this change number?

Thanks

Regards

Sreepati Hari