[aerohead]

I made photo-enlargements of 'Livermore's' work.
1) It appears that they're using 'effective' angle in a different context as 'Effective Back-Light Angle' ( EBLA ).
2) Tail 1 is 3-sided, achieves a 'tangent' angle of 14-degrees, a wake area of 78.1259-sq-ft, and a 'system' drag reduction of 24.8%, at 48" length.
3) Tail 2 (A) is 3-sided, achieves a tangent angle of 11-degrees, a wake area of 76.3516-sq-ft, and a 'system' drag reduction of 26.0%, @ 48" length.
4) Tail 2 (B) is 4-sided, achieves a tangent angle of 11-degrees, a wake area of 84.693-sq-ft, and a 'system' drag reduction of 26.1%, @ 32" length (the lowest drag of all tails ).
5) Tail 3 is 3-sided, achieves a tangent angle of 27-degrees, a wake area of 69.985-sq-ft, and the 'worst' 'system' drag reduction, @ 21.9%, @ 48" length.
6) Tail 4 is 3-sided, achieves a tangent angle of 22-degrees, a wake area of 67.488-sq-ft, and a 'system' drag reduction of 23.0%, @ 48" length.
7) Tail 2, as a 4-sided, 48" tail, qualitatively, might produce a drag reduction in the neighborhood of 39.94%.
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8) So, the 'largest' wake had the 'greatest' drag reduction! ( having a 'floor' in the boat-tail made all the difference )
9) The 'shortest' boat-tail also had the greatest drag reduction. (for the same reason a #8 )
10) An 'all-curved' tail of 2.66 meter radius ( 104.72") had no advantage, as it reached 115-degrees of arc from the virtual forward stagnation point, and 22-degrees tangent, prematurely, initiating eddy rollup and flow separation, even though it is actually 'longer' than the other three tails.
11) If the 48" Tail 2 was given a 'floor', to block the transverse pressure adulteration from below, it would likely take top honors for drag reduction.
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I've got one more thing to investigate, but it'll require a few more trips to the copy machine and light table.
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It's unfortunate for us that 'Livermore' lumped three different aerodynamic technologies into a 'system' ensemble. Untangling the drag reduction attributions for each of the three devices creates a real 'migraine.'