Are Mercs on HX more sensitive to dips than Mercs on series choke on 230V ?
If the OCV of the HX is about 230V, then not. In fact mz main experience comes from the series choke on 230V and a woodchipper: The lamp (Tesla RVLX80, on a VS choke ballast) extinguished even when I just put a bit thicker branch into the chipper, the chipper used an induction motor with a run capacitor phase shifer (so huge current variations on varying load)...
Truth is, replacing with a new Sylvania (European, so SLI lighting, not Osram) lamp, the problem disappeared.
It is the CWA (or a series LC as an equivalent on 230V mains), which is "unusually" immune towards voltage fluctuations...