There are a lot of Helia owners on this forum. You should try to contact a few of them for recommendations. Yeloya has one in his charter
fleet and could provide some insight for generator
size if you send him a PM.
IMO, 11kva is way to big for a Helia. I'd lean towards a 6 and certainly no bigger than an 8. It will be surprising that you'll have 3 individual A/C units but if it does, they are going to be small units. I love the boat though and hope you have fun during and after the build process. Keep us informed.