Hi there
First rule, is to enjoy it!!
Don't worry if Bobby runs out, its all part of the learning curve. At training you can never recreate a competition scenario, so it is difficult to get experience for your first run, and especially in open, that fab!! Well done to you and Bobby!!
As for height measurement, you put you dog under a structure, so the top moves down, and the measurement is taken. I hold a metal pole over the shoulders of mine so they get the feel. The people who record the heights are head judges, so are used to taking them, and also used to helping dogs get measured.
I have found flyball to be a friendly sport to be in, and there is always someone there who can help you with any problems that may occur.
Jenny, Harley & Mayhem