Once you start tweaking the parameters, it is often a good idea to playtest frequently to know the effects of those changes. What I would generally do is perform a quick playtest with 3-4 people, generally a combination of team members and people from outside the team, depending on who was free at the time. I would then use one of the recording techniques and simultaneously take notes. After the playtest session, I would go ahead and document my analysis, and write down the changes for the next playtest. While typing my notes, I would check if any of the programmers were free and ask them to implement some of the changes and I would implement the rest of them once I was done. If none of them were free, I would have to wait to implement those changes until I typed everything because I found it easier to write it down while everything was still fresh in my mind.

 

Here is an example of my documentation for playtests