Next Wheelset Advice - upgrade from Shamal Mille

[spinarelli]

I've seen a lot of deals for rim brake wheels recently so I got the bug to get a new wheelset. Currently, I am using Shamal Mille C15. Which I am very happy with.
I'm using rim brakes on roads or light gravel. So, no disk brakes. As far as clearance I'm using 28C vittoria tires on the C15 rims with no issue with the enve fork or the Campagnolo brakes. Going up to C17 or the wider belgium+ would I have to size down to the 25C tires?
First option is to get the same iShamal Mille C17 version.
The second is to get something hand built, like a Hed belgium+ with white industries T11 hubs, or CK hubs.
Third option is to get a second hand carbon wheelset, like zipp 303 or enve 3.4
Budget wise, would like to stay around $1K US or $1400 Canadian $.
Anyone that has experience with either of these wheels I would love to hear your opinion. Thanks, in advance!