I don’t know the quality of the superstar builds, I would trust JRA to build you a good wheelset though, I have had plenty from him and most have been spot on.
IF JRA recommend those hubs in their wheels, then I see no reason to get anything else. THey probably build into a very good set of wheels. The only issue I see is the alloy nipples, but if you’re not using them through winter then they should be fine.
At 75kg, I’d say a 24/28 combo is bang on. I’m about the same weight as you and have a 24/28 set of A23s which are fine. I’ve also got some Archetypes on DT 350s which are 28/32 and these are absolutely solid. But a bit overkill. The 350s only come in 28 or 32 hole.
There are basically only two rims worth considering I think; Pacenti if you’ve got the cash, or Archetypes.
If you’re going to get a fancy set of hubs, have a look at White Industries – they look to be about the best.
I’ve never used CX Ray spokes, but I think they’re the same dimensions as Sapim Lazers/DT revs. If this is the case, I’d go for something a bit sturdier on the driveside rear such as Sapim Race or DT Comps. They feel much stiffer and will probably last longer as well, plus they cost less. HTH