RE: Boom length???
I would recommend checking out Maui Sails' carbon 170 Wave boom. The range of adjustment is from 170 to 230 cms. The boom is a monoque design, so the stiffness is unparalleled, even at maximum extension. Also, the front end is arguably the best on the market. They sell front end component assembly, so one can upgrade most other boom brands. Just this week, I retrofited my HPL with the MS front end (fits perfectly).
I should point out that MS carbon booms are quite pricey. That might tend to dissuade you a bit, but in the long run, the investment is worth it. If you're real short on money, you might alternatively look at their aluminum boom line.