I havent been there myself but one of the guys i sail with lived there,the seasons are similar to ours so May isnt the windiest period, i believe the sail choice is 4.5 to 5.5 90% of the time which will mean a small board would be used...leave the 133 at home!
I believe there are all the international hotels on the beach, these may be expensive so it depends what you want,there is a hire shop which specialize in gear that works well in their conditions, its good to hire as you can experiment as much as you like.
Have fun.

Mate,
Check this old topic out.
Cheers

www.seabreeze.com.au/forums/topic.asp?TOPIC_ID=22319&SearchTerms=noumea

Hi Mate,
I sailed Anse Vata beach September last year and it was fantastic. I was on a cruise ship that had a single day stop over in Noumea. There is a hire place on the beach which had 06 model prydes and JP rigged and ready. I used a 8.0m V8 on a 135 xcite ride which was fine. You can catch a bus from the centre of Noumea to anse vata for a couple of bucks and I think I paid about $60 for 2.5 hours which included everything. You will need a bond of about $100 which you get back. The day I sailed was a Saturday and their where heaps of locals on the water and everyone was sailing from the beach out to some islands and back. The guys dont speak much english but lucky for me the french word for boom is boom etc...
Noumea is expensive and you should expect to pay 30% more for everything as it all has to come from France.
IMHO I would hire the gear off the beach when the wind was up.
Cheers,
Chris