IMHO the long reach is more for sloping than mass excavation. If you compare a dragline and a hydraulic long reach of the same size/weight the dragline has a bigger bucket. The disadvantage of a dragline is you need a very skilled operator to run and maintain one. Not as many skilled dragline operators around as there used to be. If you don't want to use a dragline, maybe instead of a long reach trackhoe, a large standard trackhoe like a 365 or 385 could be productive. I don't know how much experience you have with draglines, perhaps you could rent one with operator from a contractor in your area.