I think a 120cm board would be too small for you. My girlfriend is around 100 and she rides a 131.
Here is a cheap 128cm board:
http://www.evo.com/outlet/wakeboards...mens-2013.aspx
This would be perfect for you, in my opinion, same board as the August, just bigger.
What bindings are you using? In my experience bindings can add a lot of weight to a set up.