Zoro; do the races you enter not have a minimum bike weight? While I applaud your quest for lightness, does running wheels like this not put your bike under the weight limit for racing?
Yes - by 900g/2lbs. Racing weight with two cages and pedals and DA DI2 is just a hair over 6kg/13lbs. So when/where it matters - we need to add weight. I had another thread asking the best place to add weigh. I will use lead weight below the BB for this. I'd still use light wheels and add lead to the bike.
As for the topic of the thread that you are sternly pointing us all back in the direction of; the lightest wheels I have are AX Lightness SRT 24, on Extralite hubs. They are not the same rim size as your wheels here, however, so not comparable. They are bloody light though.
No debate on the SRT 24 if what I read is correct on their specs. And they were what I was going to buy. Note last year we used RZRs (900g) with Veloflex Records (190g), and decided for real racing we wanted more there - and a stiffer/more plush ride . There are 1-2 races and a TT the SRT 24's would be better for - but no more budget. The M5s are a better choice for 80% and light (1110g with skewers). We use the Extralite hubs.
I have built a load of Far Sports on Tune hubs which are in the same ball-park, weight wise, but again, with smaller rim height (24 and 38, mainly). They are a good option though, for someone wanting very light racing wheels; I like building using a high end hub, decent spokes, and a cheap Chinese carbon rim, as I view the rim as the next expendable part after the tyre, especially in racing, so when it inevitably gets trashed, rebuilding with another cheap rim onto the same spokes / hubs is only a case of a couple of hundred dollars, rather than mega-bucks.
I often see the Mercury M5s compared to cheap Chinese carbon rims, or the Gigaxxx ones. M5 rims are made in Taiwan and somehow associated with the same company that owns Harro bikes. They also are easy 100g lighter per rim than any other open mold/chinese/Gigaxxx rims specs I've read. It seems about the same mass per dimension as the ax-lightness rims (I am unaware of ax-lightness in 25mm width) and I have not seen that carbon pattern anywhere else.
I am still wondering if these are the lightest *ready-to-race* 50mm+ X 25mm+ X 25mm+(tyre) complete wheel set set out there.