AdSense large font using classic code model

What are the variables that change font size in classic AdSense code.

[wildfiction]

I'm still using the classic AdSense code on my site:

e.g.:
...
google_ad_width = 120;
google_ad_height = 600;
google_ad_format = "120x600_as";
...

What variables can I add to change the font size? I have been unable to work out how to generate the classic code from the AdSense web site.

Thanks

[Lame_Wolf]

Go to "My Account"
There is an option there to alter it.

[wildfiction]

Thanks Lame_Wolf - that worked.

[Lame_Wolf]

nps :)