RE: Props rotation seen from stern?
Really it should be what you prefer.
If "A" works better use A, if "B" accomplishes what you want use B.
When I was taught to build model boats, I was told to over size the rudders by a fourth, or
enlarge the surface area by 125%. We used to draw the rudders on to graph paper and
count the squares, then add an appropriate number of squares to get the rudders 25% larger.
If you are up to building some new rudders, then by all means give it a try.
But don't throw out the old one,.. You might want to switch back.
How many rudders does the PT boat use?
Are they behind the propellers, or between them. That might make a difference.
More than 35 degrees of rudder usually acts like a speed brake.