I use these to look at say, efficiency, such as speed in relation to task. If I should be the lead judge in the pit, I ask my fellow judges to be responsible for areas that we evaluate. I do not want the team members to even realize that I am there. They have enough to worry about. In events where I am the lead judge, I always remind myself and my cohorts to try and be invisible to the team, but at the same time get whereever you need to in order to see.
Consideration is the word.
This year we are going to push for the Judge's to be in bright colored vests in order to for team members to not be confused. Each team starts at a mark that's not a one and not a ten. To say where I start each competition, I could'nt give you a number. Generally though, I think we as judges are looking at 4 to 6 as a good performance by a team. Remember you have 130 possible points as a judge, so there is plenty of room for you to add or subtract.