Katie,
I have a tendency to agree with the amount of time it takes for the hyperventalation thing,.frankly I think I know people without epilepsy that this particular excersise would give a siezure...When I did it, many years ago, they could not get me to seize...I felt kind of like I had beat it..but the test showed different...
I went through a vigours excersize program a few years ago, and was running 6 miles a day..(I am not a runner) I never had a seizure, but frankly many times wished that I would so I could just sleep...