Its nice to see a few carp anglers posting on here lately and I hope some will stick around for a while and help answer some of the many questions asked. :w
I'm no out and out carper but I do know the Black Widow is a favourite amongst many commercial carp anglers, I suspect its due to the 'easy to remember' name rather than performance that accounts for its popularity? Not that there's anything wrong with Diawa stuff, indeed they produce some excellent budget gear whereas the Fox is generally considered higher quality but it causes too many moths to fly out of the old wallet imo.
Personally I'd go with a 2.75 test on UK commercial type venues, your unlikely to encounter anything big enough give you problems.
Here's another for you to consider;
TF Gear Banshee 11-13' Allrounder Rod in Feeder Rods | Fishtec
Its not as trendy if you like to follow the crowd and its certainly nothing to brag about either, but it will do the job asked of it Bonus? you also get a free reel to go with it good luck.