I like unsweetened tea!
My expertise comes from owning two 12's one 20 and one 16 gauge Darne.
I only retain the 16 gauge but any of the Darne's I have owned would do the job and have ranged from 6#'s 4oz to 5# 12oz.
The 16 is a custom Bruchet Darne Ted ordered for me and is a cut above the earlier models with an unusual double trigger system.
The 28's usually were of the higher grades but as Ted points out, there isn't enough information given in the Original Post to make any valuation.-Dick