i'm alex of the school kitesurf vietnam.
about your question about spots...my question is waht is your level and equipment.
phan rang offer you in two spot flat water in the lagoon and wave in my ai. but is super windy.
often people of 75kg need a 5 mq, to visit the lagoon you need a permit.
so it's better to go there with the schools that arrange a trip of one or 2 days. from mui ne you need 4-5 hrs by bus
the city of phan rang is very big..but no amenities for foreiner tourist. so if you don't want to get too bored is better to stai in mui ne and after you move with the school trip to see other spot.
on many beaches there is the problem of fishing lines..is a trap for shrimps and crabs with floating lines of 50 mt...and you can have a set of 10 fishlines at 3mt each for hundreds of meter..close to the shore. so for that reason the safe spot are: turtle island, jibes 2, malibu, mui ne , ke gha.
about harbour of phan thiet..better that u take vaccine for all knowed deseases.
turtle island and malibu..you can reach with the motor bike..driving about 30 min - 1 h.
so often you can find other kitesurfer so it''s essy to go there alone and enjoy.
ke gha is 2 hr by bike...so you don't find anybody. ke gha is goood for big waveriding up to 3 mt. i love it!!!
about kite size 7-9-11 for mui ne and close spot, 5-7 for phan rang (for a kiter of 75 kg)
so for phan rang and ke gha is better that you go with the schools trip.
the island that u ask me..you need to be equipped with 5 mt..it's beautifull..but no service for tourist..
in the night no electricity..and if the sea is too big..you risk to be isolated for one/two week.
honestly..if you go there with your wife...that day after she ask for a lawyer.
a frind of mine whent there for windusrf..he enjoy but everyday with 3.5 mq of sail
phu quoc is in the gulf of thailand..so no wind at all.
in mui ne you have many option for bar, restaurant, disco, shop. so for sure both of you will enjoy.
about our services we provide: lesson, rentals, airport transfer, visa service, booking accommodation hotels or guesthouse, or villas.
if you have other question..u are welcome
all my best