Here are a couple more links:
http://www.weatheroffice.ec.gc.ca/as...parence_e.html
http://www.weatheroffice.ec.gc.ca/astro/seeing_e.html
They use a 1-5 scale, but same theory applies.
Think about it this way guys:
Transperancy is a measure of how much crud is in the air. More crud (dust, smoke, humidity) the less faint things you can see: nebula and galaxies.
Seeing can also be referred to as steadiness. You can have crystal clear skies, but if the jet stream is screaming overhead, the image will be all jumbled like the air over hot asphalt. The steadier the image, the better for planetary and/or double stars.
The effects of transperancy can be negated by light pollution or the moon; however, seeing isn't. But good seeing can be negated by doing something silly like looking over the roof of your house in the middle of a cold night.
Hope those links and thought help!