It is very hard to say exactly how long your downloads will take since every ISP and connection is slightly different, as is the varying load on our server: your mileage will vary.
That being said, you should be able to get the larger HD files which weigh in at 500 MB + in less than three hours - probably much shorter - if you are lucky, about 15/20 minutes...
Remember to disable any download manager and download only one file at a time
Let us know how you make out
CS