If he's got the first question then I've got the second!
Your URL channel needs to be the 1plus.net address.
http://1plus.net/mydomain.com/
You need to bear in mind URLs like this -
http://1plus.net/?news=golf.sc&term=golf+supplies
will not get added to your Adsense URL channel. I don't think there's anything in 1plus that makes those URLs but I have had a few posted on this thread so my Adsense totals got screwed.
You can use those URLs to change the news on your domain if you want to check different words out for example. So long as you don't use them, your URL channel will count impressions/clicks just fine.
I found it's better to use a custom channel on every domain although manually entering Adsense codes for all your domains is quite time consuming.
