Welcome to the forum Spenceey.
Chrinas on Ultegra hubs would make ideal audax and general purpose wheels and Spa apparently build them very well. I would choose 36h rather than 32 though - the weight difference is minimal for a significant benefit in durability.
Some people here have had durability issues with Zenith hubs, so make sure you research those properly before committing to them.
Chrinas are excellent rims and have a thicker braking surface than Open Pros, so they are more durable, albeit a tiny bit heavier. They are very popular with audaxers.
I personally use Open Pro Ceramic on my audax bike, which are lighter than Chrinas but don't seem to wear at all due to the hard ceramic coating on the braking surface. Spendy though and you need the right brake pads for them.
A lot of people here build their own wheels too - it's not difficut with patience and the right kit - if you want to find out more get hold of Roger Musson's ebook from
www.wheelpro.co.uk and have a read. There's an advantage for audaxers in learning to build wheels as you are then able to maintain them confidently on the road if you ever need to.