We use the DME Arc fairly regularly to facilatate arrival / departure procedural separations. It certainly makes life a lot easier from the ATC perspective. I have also used it to position an aircraft so I can sight it and then provide a visual based separation.
One question I have is can a DME Arc be joined from the inside? We have fairly high terrain some 15 - 20 nm to the north but published altitudes on the Arc do not reflect this, presumably because an aircraft joining would normally be inbound towards the VOR before turning onto the Arc (thus clear of the terrain). I have found nothing that specifically precludes the inside joining procedure but wonder whether the published Arc altitudes have been calculated to allow for an inside join and the relevant navigation tolerances applicable. Anyone have any ideas?