Schematic of the GROND optical (g′r′i′z′) and NIR (JHK) channel spatial coverage at a redshift of 6. The dashed boxes are the respective g′r′i′z′ FOV for each individual telescope dither position; a similar pattern applies to the JHK channels (not shown). With most of our targets being within 1 arcmin from the centre of the FOV, and since we require the r′i′z′ bands, our conservative search radius is 80″, corresponding to about 471 h⁻¹ kpc proper, or 3.3 h⁻¹ Mpc comoving.