As a general rule, Wave I is done when 90% the participants in Wave I have a KCS license. The level of license required for Wave I participants is dependent on your licensing model. The goal is to have the knowledge workers in Wave I doing their work without intense coaching. The Wave I participants' workflow and articles should be sampled through the Content Standard Checklist and PAR process.
Once Wave I is completed and the technology, content standard, and workflow have been updated based on the Wave I experience, we are ready to deploy additional waves of adopters. If the additional waves are in same domain as as Wave I or are in different domains but using the same (updated) foundation elements from the design session (content standard, workflow, measurement model) we essentially repeat the activities we did in "Preparing for Wave I."
One key difference for Wave II and beyond, however, is we now have more coaches - coaches who have experience with KCS. The number of coaches that came out of Wave I can help to dictate how many knowledge workers can be in Wave II, if you haven't already planned for that.