Client Deployment

I would like to see an option in the deployment to have it schedule for a certain time.  Right now we are having to deploy while people are working and there is a slowness that occurs in the hour after deployment.  While the system is updating virus definitions and doing it's first scan, some of our systems slow down considerably and some lock up alltogether.  A reboot fixes the problem but if there was a way to schedule new installs for sometime when users aren't working (like in the evening), that would save a lot of time.  If you could incoroprate a Wake-On-Lan option also, that would be even better.  I talked with tech support and they have the depayed deployment  for systems that are upgrading but not brand new installs.