I would never be able to turn my head side to side 3 times a second. It would be too rough on my neck and cause other problems. I timed myself and I can do one head turn to one direction per second. I know that I cannot do it any faster. Just 10 turns in 10 seconds has caused my neck to tense up. The noise in my neck is quite noticeable. A headache is developing.

The up and down movement would also be rough on my neck.

There is no practical need to move your head any faster. Maybe you can do it at a slower rate for a while then build up to the faster rate.

If you want an enjoyable way to do the second exercise, try doing jig saw puzzles. They require a lot of back and forth and up and down eye movement as you look for pieces that fit. I do three jig saw puzzles a day at Jigsaw - MSN Games - Free Online Games
There are others that use larger puzzles on larger screens.
I use the edge and arrange functions as I do the puzzles.