I wouldn't have thought they were a viable choice together. Buenos Aires are boisterous and fin nippers at best, rummy noses go best with Cardinals and the like.
Buenos Aires like the low 20s, and all 3 species sold as rummy noses like it warmer. Add to that what @itiwhetu said above, and it's not a mix I'd expect to work. Buenis Aires are a larger, heavier fish, which when you add that to their bashing crashing ways, would be rough on gentle little rummys.