Good stuff spike! i've never had the chance of firing a professional show by hand, we always use a firing board or fully digital.
i work with Pyro Spectaculars (Souza Fireworks) do the Pacific Holiday bowl each year (free field pass is a nice perk lol) bunch of 4th of July shows and such. biggest shell i've shot so far was a 10" off a barge

weren't supposed to have anything over a 6" on it cuz it was small lol!
heres a pic from Camp Pendleton show, you can see the gun racks/troffs in the back left...and how serious we are about our job
if your ever doing a show near FL and need an extra guy on your crew, i'm totally there!