Setting up a scale of collection3 graphs

Question

We use collectd to monitor a lot of stuff inside our app. It's great. We also use collection3 to display the data collected. It's great too, but the doc is either very well hidden or not written.

So basically, we have this graph that shows a percentage a late feeds (we're a feed polling service) and I want to make sure the graph displays on a 100% scale. Ideally, I'd also want an adjustable color : red when it's above 10%, orange between 1% and 10%, and green when it's below 1%, and maybe smooth lines.

Right now our collection3.conf file looks like that:

<Type late_feeds>
  Module GenericStacked
  DataSources value
  RRDTitle "Late Feeds"
  DSName value "Late Feeds"
  RRDVerticalLabel %  
  Color late_feeds ff3f3f
</Type>

Any clue?