iv been fortunate to have shot several bushbuck when i was younger with a rifle
last year i killed a beautiful old Ram with my longbow walk and stalk in a river bed.
everyone one knows im no fan of sitting in a hide, and from my experience i believe its pretty uncommon to see a bushbuck at a waterhole with a blind unless there is no water anywhere else. The old rams tend to have secluded little springs and water holes deep in thick bush and riverbeds.
Bushbuck are mostly solitary or in pairs and like thick riverbed bush so thats where i would suggest you hunt for them, arrow nocked and walk very very slowly if the wind is good you can often get right up on them, however getting a shot and keeping the noise down is tricky due to the thick bush, always a good chance of running into a rooting warthog ( that i know Jon wont pass up :D ) or a big kudu hiding away from the hot sun.
The rams can be quite territorial so if you see one in a particular spot feeding he'l likely be there the next day at the same time.
Speak to the trackers and ask where they have been seeing them.
some of the big rams i believe have a 6th sense and for no obvious reason when your stalking them they will just trot away seemingly un alarmed and the stalk is over.