the "standard" gunset for POW is the 14'' L versions, quad on the big slots and dual on the middle one. they don't block (have worst spread of all uk bb3 guns), but have real bb3 range (though still bad compare to other nations). you can AW with 2 front guns using either N and L versions. You can also try 16'' Mk1 guns for Nelson, which have same range as the 14'' L.
When I played the POW, I used both the "standard" speed whore setup with all 3 guns and AA, getting 40 knots. I also tried the 2 gun speed setup like you said. I have never try AW with any UK ship. I find that the standard setup is more consistent, but when played correctly, the SW setup can be deadly. I am not very good at it either, but I have faced SW POWs and it's a scary sight to see if you let them get in range and they know their angles. Ultimately, it's up to you to decide what playstyle suits you best.
