I think I have mastered manual targeting.
Third target: I set range and Aob reading at 6,900 yds/32 degrees Aob left per the Kiub dial. I fired with the Aob +/-76 degrees left (per the ship's dial)/ bearing 17 degrees/range 2200 yds. I fired a 4 degree, two torpedoe spread. The first missed aft and second hit right below the target's stack at its stern and blew it up. I decided to try firing at other than a 90 degree angle to test the accuracy of the Kiub dials, and see if I could hit a target without firing a 4 shot spread. It worked. The key is familiarity with the Kiub dial.
Karamazovnew advises that I should not be seeing mast heights or ship depths in feet, so I may have to delete the Omegu English mod, as it may be creating that problem.