With a type VII mid-war in GWX I pull 40 tons or better out of a good convoy attack. Getting right into the columns, where the big steel is. Convoy attack tactics are not something a new player might be able to just jump into. So maybe once you get into a French port, try patroling BE, more specificly the upper right quarter of BE. You'll find Tanker alley and a few doubles now and then. Convoys pass thorugh there too sure. It's a great spin up for mid-to later war.
Btw your machine sounds ok, maybe double up on your ram.
