rangout

Hi I have a really basic question regarding OS Deployments. We currently have an SCCM environment, with MDT, and are ready to test our Windows7 build. This is for a desktop refresh that will use USMT, which will re-format the hard drives. Before it goes live, we need to produce some timescales for our live rollout. Is these a method to calculate the number of deployments we could carry out over a single night? We already know our network speeds, and number of users per site. We need to get it complete in a set amount of time, but do not want to push it out to too many machines in the one attempt, then sepnd the next day re-deploying the failed installs Thanks