Jay just for your information:
Westsail never made a 33. You have something else!! let me repeat: You have something else!!!
I don't know the laws in Aus. but your broker (sales person) may have committed fraud selling a (Westsail 33) ? Don't know and I am not a lawyer so?
To this end, and because it keeps coming up on the board. Could you find out who the builder of your boat really was? (names of people), and post it here, so when others ask, we can point them in the correct direction. (if it is a well built boat, they should be proud to list their names, or be found through internet searches.). If they did counterfeit on the Westsail name, I am sad to see your country allowed it .
But for your questions,
height: when standing down in the cockpit, the boom on my W32 is about 5'-11.5" or 1.82 Meters from the cockpit sole. This could be raised up to 1.9 or 2M based upon your size and how much further you can raise the main (should have at least 1" or 3 cm clear from shives at the head.)
as for shortening the length of the boom ? Please sail it for 2+ days, then if you have weather helm (and or) if you want to raise the boom, then you could cut some off, and have the sail recut to fit. Make sure at the highest angle (last reef normally) it does not hit the back stay during a tack. The reduced sail area will lessen your drive a little +/- 4% when the wind is under 12kts, but above this wind speed it should not make much difference. I would say you may only give up 0 to 5 miles / day ? I have shortened my boom, so that the foot is 14' or 4.27 Meters long with good results for what it is worth, as I have a W32 made in the USA. If your boat builder had information on how Westsail 32's sailed They may have moved the mast forward 4" to 6" and if so, would mean you need a bit more than the 4.27M like 4.43?? but it would be hard for me or anyone else to tell without sailing your boat.
Best of luck:
Norm
p.s. posting as a "have a boat like the Westsail 32" in your title, would be most kind to others reading the board. or a "33 Built by Australia Westsail / Not the USA Company" would also be a kind way to let others know, you are talking about an Australia built vessel and would lessen the disrespect you get from Westsail owners.
cheers and fair winds.