My advice would be forget the instrument rating until you have AT LEAST 700 hours total time.
Do the C cat instead (not the 20 thousand dollar one though!).... even if you never actually end up instructing, the course itself will hone your basic skills and knowledge as well as open up a few more job opportunities.
Leave the instrument rating until you have the hours to start hunting for twin jobs. (in NZ 750hrs minimum for part 135 air transport).