I move around the course every year and Glen Helen is one of my posts every year.  Try it is a great spot.  There are many different points that you could be assigned to, all very good viewing.  Another nice point is that are are several food trucks that set up in the parking lot now that the Glen has closed so there is food and drink available.

Several others that I can heartily recommend are Ginger Hall, Sulby Bridge and Hillberry.  There is no food ar drink available at the last two but if you have been working on the mountain that should not be a problem for you.
Bill