Heavy artillary was funny,..and shawn as a wizard should be very humorous
If you do decide to do a flashback, which I understand your still deciding I have and idea for one...
Pardon my first draft writers ideas, there blocky
Shawns dad comes home to find a bunch of boys on hobbie horses running around the back yard, play sword fighting
cut to henry sitting shawn and gus down...(gus has a paper crown)
Henry: what where all those boys doing in my yard?
Shawn: we where playing King aurthur, and the knights of the round table,
Henry: shawn you know you can’t just go inviting all your friends from school over into my yard swinging plastic swords around, someone could of gotten hurt .
Shawn: Dad it’s hard to play king aurther when it’s just me and gus, we need more knights. King aurthur and lancelot never won any battles alone…
Henry: shawn being a knight is more than just winning battles and waving swords around on horses.
(yada yada if you like it work your magic to make it sound better more like the show)
Henry then goes on to explain to the boys briefly about chivalry then pointing to a girl out side, it comes up that shawn wouldn't let her play...and then henry explains what shawn andgus should do to be nice to the girl, gus seems to get it and walks out side shawn is reluctant but with a glance and a "shawn..." from his father follows.
i know it mgiht be a bit much but like i said work your magic on in if you like it
another idea is that the girl in the beginning could work at the renisance fair, and could maybe hold a half grudge at shawn, maybe a little crush though as well for tensions sake maybe they attended high school together
and if gus was a jester maybe he coudl referance back to when he played king aurthur " you know shawn i was king aurthur once... how did I get to be a court jester" "dude we where like 10 ( insert age I don't know) your crown was made of yellow concruction paper and it bedazzeled"
any way just some more ideas