I had the smallest Wacom Intuous 2 at one time, I think it was a 3 x 5. It looked like a good size but the working area was actually only 3" x 5" which I found impossible to work when it came to trying to relate that size space to a 17" monitor. Plus I think there was something wrong with it because it wouldn't hold it's install and practically everytime I went to use it I had to reinstall the program and drivers.

Earlier this year I bought a new Wacom Inutous 3  6 x 8 and TBH it's being used as a giant coffee coaster.

Trying to equate a 6 x 8 inch area to a 22 inch monitor seems impossible to me, not to mention that I can't get my brain around using a "pen" instead of a mouse. Not to mention the "disconnected" feeling of working on one surface while having to watch another.  I just seem to manage better with a mouse, even for fine details.

IMHO I think it's better to get the largest tablet that you can afford.

"It is good to see ourselves as others see us. Try as we may, we are never
able to know ourselves fully as we are, especially the evil side of us.
This we can do only if we are not angry with our critics but will take in good
heart whatever they might have to say." - Ghandi