Interesting TINAS, you’ve lost 250gm over mine which have 32/32 15/16 guage spokes and a 105 rear hub (I like cheap cassettes!) (and my point you quoted was in reference to the bloke saying it was easy to get a 7.3kg bike then said it was Super Record etc).
I rebuilt my rear with spoke washers.
I’ll be mostly in the hub, they’re scarily light. Although unlike the A2Z on my MTB when I took them appart there’s nothing scary about them, they’re just very simple/minimal. Whereas the A2Z I suspect will break it’s axle at some point as it’s not well suppourted.
I used washers and plenty of grease as they’re the original Alphas with less material in the spoke bead.
That build’s DA 7800 shifters/mechs, PX brakes, FSA SL-K chainset, carbon post, ritchey WCS alloy bars and stem, so not budget either (but not super-record!), but the groupset was bought 2nd hand. Just proves that a build nudging the UCI weight limit is possible without breaking the bank, and most of the 2nd hand bits would be even cheaper now than when I bough them.