Way to go there, SC. That's a decent group by any standards, and especially good considering your experience so far at handloading.
With that, you're off to a very good start. The 39gr SBK has been known for very good accuracy in the .20's, but I've not seen much in that department regarding the Speer TNT by comparison. I'd concentrate on the SBK if it were me. You might also consider trying the 32 grainers for PD's. They shoot much better than you'd think under 350 yards, and lets be honest, most rat shooting takes place at or under 350, no matter how many "long pokes" you take.
I just returned from over a week in the rat patch, and once again, I was amazed at just how well the 32gr performs in the field, even in moderate wind conditions. My long shot this trip was only 402 yards (ground squirrels), but it was in a full-value 8 mph crosswind. So don't ignore the 32's, as they're also easier to find at this point in time right now.
That 402 yard shot was taken here at the distant fence line seen in the pic. My wind flag is not in the pic, but it was at a 45* angle, telling me the wind was 8-10 mph at the time of the shot. That rat launched at the shot, doing a magnificent gut-flip. Rat exiting stage right, his guts to stage left.
Always entertaining.
One more tidbit.....your group is very nice indeed. Now experiment with seating depth with that same load. You may find the "Pet Load" you're looking for, and be even happier.
