¹²CO moment-zero maps of the six sources from the “low S/N sample” (see Sect. 5.1) where the S∕N = 3 contour of their ¹²CO emission, shown in cyan, reaches beyond 4 × R_mm. Using this contour as a proxy for R_CO, these disks likely have R_CO∕R_mm ≥ 4 and are therefore clear candidates for having undergone dust evolution (cf. Trapman et al. 2019). The top three disks have resolved continuum emission and their R_{mm, obs} is shown by the yellow ellipse. For these sources, Keplerian masking was applied to the ¹²CO J = 2− 1 emission (see Appendix A). The bottom three disks have unresolved continuum emission. The dashed yellow circle shows the size of the beam (0.′′ 25) as an upper limit to the dust disk size. Similarly, the dashed green circle shows four times the beam size.