You are right, there are indeed cheap ultra lightweight Chinese components.

But would you really dare to ride with ultralight cheap Chinese carbon seatpost, handlebar, saddle... ? I feel safer on Schmolke, AX-lightness... ! Remember that some (expensive) carbon stem for Brompton broke.

For the Clavicula SE, well 120g in absolute seems not much, but 120g less with a weight of 390g is about 24% less, quite a lot in relative saving.

ETRTO 520 is a junior or female road bike wheel size, it is the 24" race road size (while ETRTO 507 is the 24" BMX size). Terry has some race road bikes in that wheel size.

There are few tires available in ETRTO 520 (Durano 23x520, Panaracer Pasela 25x520 , Terry Tellus 32x520 and I think tha'st it). But it should be possible to mount ETRTO 520 wheels on the Helix (total diameter with Durano 566mm, with Pasela 570mm, Tellus 584mm, total diameter with original wheels+tires 587mm, assuming that the announced width of the tires is correct). It should be possible to custom built some lightweight wheels in ETRTO 520 with Velocity rims (Velicity has (at least had) good rims in ETRTO 520.