From which larval stage, inc dauer, does the rol phenotype become sufficiently pronounced that it would significantly impede the mobility of worms carrying rol-6-containing arrays to traverse a plate to a new food source or other attractant?
You may be able suppress the Rol phenotype with some Dpy or Lon mutants. I have done this for example introducing dpy-5 him-11 into a rol-6D transgenic strain so that the resulting Dpy (non-Rol) males could be used for mating. In principle RNAi targeting a Dpy gene should be able to produce enough transient suppression of Rol. Note that RNAi of rol-6D would probably produce a Rol phenotype anyways, as the loss of function phenotype for rol-6 is also Rol.
In addition to dpy-2 and dpy-10, sqt-1 function is also required for the Rol phenotype. You could use LOF or RNAi for any three of those genes. If you need animals to mate, don’t use sqt-1, but if that’s not an issue I’d recommend using sqt-1 RNAi.
I have used the sqt-1(RNAi) trick for a rolling transgene and had limited success. I won’t strongly recommend it, but one can get it to work.