For chub and barbel on The Wye a big feeder, frequently recast, with pellets, is what you want. Finding the barbel is more important: you need strong flow, deep water and a gravel bottom. The staff in the Docklow shop will tell you the right pegs I'm sure but make sure you aren't undergunned with your rod/line etc, especially if the river is up. Last week, in ultra-low flow, there were pegs where I needed 6oz to hold bottom.
Definitely don't use a pole on the Major Bill lake. The carp are all doubles and there are big cats. You need proper carp tackle, a bolt rig etc. If you haven't done "proper" carp fishing it's a great place to learn as there are loads of them.