I'm currently off southern Portugal, fairly close (but not too close
) to the entrance to the Med. It's July 1940 and there are lots of convoys with large merchants and large tankers (rubs hands). They do however have quite strong escorts...
As for BBs etc. the Revenge I sank earlier in this career was in the middle of a convoy in the Western Approaches. Also got a Fiji cruiser inside Loch Ewe. Have also seen but not attacked Task Forces in the North Sea.
This is all with GWX not stock.