Kristen,
Seeing as how I'll be "breaking in" your GT-500 before too long,I found a game to hone my skills a little.
It is a Reaction Time game with the 'Christmas Tree".It uses the Pro lights.
My best so far is a .061 rt.
http://www.pedregonracing.com/rt_game.asp
EDIT: Make that a .03 rt