Basically, you don't know client bandwidth, so that the first problem.
To limit bandwidth on server side use:
Client.setBandwidthLimit(servertoClient, ClientToServer)
Tipical meters:
Modem: up->33, down->33
DSL up->100, ->down->400
LAN up->1000, down->1000
To apply on server side use this method on a clientObject like this:
clientObject.setBandwidthLimit(1000*33/8, 1000*33/8) //Modem
Jorge