I SOS chained Carbink for a Sableye on my UM because I needed it for the Pokédex. I found a shiny Carbink before I found a single Sableye. Keep that in mind if you choose to go this way.
If you have another game, it would be easier to HA hunt in ORAS. It’s a version exclusive I believe, but you could DexNav chain the HA there.
Otherwise, SOS and skill swap might be the best way to hunt it though.