This is the same conundrum that I have encountered. I recently sold my CX wheels with Iron Cross rims because, while light, they couldn't hold road bike tire pressures. I wanted the option to ride both. I ended up getting a set of those Hope 20Five wheels from Merlin Cycles for a crazy cheap price and they are rated up to 110PSI or something like that. Plus I like Hope hubs
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I wouldn't use the Arc24s for high pressure purposes. I think the industry standard is HED Belgium (I have these on my rim braked bike and they feel very nice and solid) or the SL25s.
Cant wait to see the new build!