Combining CS with Larger Configurations

Does CS do as good a job as C configuration at filling in the spacings missing from the larger configurations? Figures - show the uv-coverages obtained when combining a long (HA= $\pm4\rm\,hours$) A or B configuration observation with a shorter (HA=$\pm1\rm\,hour$) one in C-2 or CS-2 configuration. The B+C and B+CS coverages are both excellent, although the latter does have small holes at $u\sim\pm5\rm\,k\lambda$. A+C also gives quite good coverage, with C-2 doing a good job of filling in the central hole and relatively light interior coverage of A configuration. CS-2 certainly plugs the central hole, but there are distressingly large gaps at $\sim5\rm\,k\lambda$ which might compromise the imaging of very complex structure. This is difficult to quantify, because the effects will be subtle and highly dependent on the detailed structure of the source being imaged. However, it does seem likely that observers engaged in such high dynamic range imaging would not be satisfied with A+CS, and would probably ask for B configuration as well. In practice, only a few experiments currently combine A and C configurations without also including B (B. Clark 1998, priv. comm.).