Why not use two pieces of 1/2 x 4 flatbar that is 8" long and then it matches the "minimum dimensions" shown in Fig. 4.37?
Curious why you want to deviate? What advantage does it gain you to deviate I guess is a better question.
I'm going to say that the "minimums" are listed in Fig 4.37 for Option 1, and Fig 4.33 for Option 2.