I’m using adsense for a lot of sites, and I’ve used a lot of adsense modules/script for many other cms.
Now my little opinion is there are too much things to set adsense with a snippet :
google_ad_client = '.$account.';
google_ad_width = '.$width.';
google_ad_height = '.$height.';
google_ad_format = "'.$width.'x'.$height.'_as";
google_ad_type = "text_image";
google_ad_channel ="";
google_color_border = "333333";
google_color_link = "C94093";
google_color_bg = "FFFFFF";
google_color_text = "333333";
google_color_url = "6C82B5";
I use chunks (naming adsense 468x60 adsense 120x240) and TV for front/backend, and works great to change size of adsense banner or switch with other banners.
a better solution should be a module to set default parameters (account code, channel..) and a preview

for different size of banners...something like EPG gallery module.
....but it’s only a dream ’cause i’m not a coder