The Railway bridge or bridge at the hotel? Both do deliver the odd cob, remember many years ago seeing a siza cob caught in Hopefield. Even caught steenbras at the hotel bridge
A pro will correct me I'm sure, Cob feed lower in the water column, but will take same bait. Maybe put a pan size elf out as a livey, you never know. As far as the grass goes, use smaller swivels, maybe a sliding ball sinker above your hook snoot, same rig as used when drifting on a boat, i think.