No offence or anything but how did you end up getting a job as an instructor if you've never owned a board? 1 week a year is not a lot of riding experience. (not bashing in anyway i swear, just curious)
You don't need 2 boards unless you dedicate days to riding one thing(park, pow, etc). If its burton you're after you can always go with the Custom/custom v rocker which is a multi tasker. I spent the last 2 years on a Custom v rocker and have no complaints. The only thing i hate about the new burtons is the Channel set up which means you can not use the bindings on any other board.