Test curves are barely relevant to the size of fish expected. Match them up to the weight being cast and the distances involved rather than the size of the fish. I can't think of a single one of our local commercials where I couldn't land the likely fish on a 1.75lb barbel rod. If you are going to use smallish leads (likely) and/or short chucks (likely), you really won't need much more than a barbel rod. Unless you start increasing the lead sizes, distances being cast or add PVA bags/mesh, you won't need a higher TC rod.
P.S. 10-15 years back an 11' 2.25 rod was pretty old hat. The high TC arms race had started in earnest by the start of the nineties. I recall my first proper mid-eighties carp rods being 1.75lb, the same as what's now considered a fairly average rating for a barbel rod. I then bought what seemed incrediby heavy rods (2.5lb) in 1993. I couldn't bear the thought of buying 2.75s. These days 2.75lb rods are often as light as most ranges go.
