HTTP/S is able to do resumable downloads, which I think is why @donmontalvo was asking that question. Except that its a known fact/issue that the "resumable" part needs to occur within a certain very small timeframe. Is it 5 minutes? I forget, but something like that. IOW, if the students are closing the lids, taking them home and bringing them back in the next day, that window of resuming an interrupted download is long over and it needs to start over again.
As for targeting the machines again, you should just be able to flush the failed policy log for those Macs to have it run again at the next trigger, not set up anything new, or am I misunderstanding what you meant by "create a new one to target the machine again"?
