1. chain (1)-(7) gives a = 0.00115964619855784; closed form (8) = 0.00115964619855784
2. data need j+k = 1.30495 (electron) and j-k = -3.33132 (muon)
   with j = -1: k_e = 2.30495, k_mu = 2.33132  (Aspden 4/sqrt3 = 2.3094); asymmetry 1.14 %
   sum k_e + k_mu = 4.63627 vs Aspden 8/sqrt3 = 4.6188 (-0.377 %): this sum is what sets the muon-electron difference

3. 21 variants (7 inner radii x 3 mass forms), ranked by electron error:
   half Thomson cross-section (Aspden)  spin mass excludes E_out (j=-1, Aspden)    a_e   -5.158 ppm   a_mu   -25.55 ppm
   Thomson-sphere radius 2/3            a = E_out/mc^2 (j=0)                       a_e   -32.91 ppm   a_mu  -2324.0 ppm
   classical radius                     spin mass excludes E_out (j=-1, Aspden)    a_e    353.8 ppm   a_mu   -386.1 ppm
   half classical radius                a = E_out/mc^2 (j=0)                       a_e    353.8 ppm   a_mu  -2711.0 ppm
   zero (point reflector)               a = E_out/(mc^2+E_out) (j=+1)              a_e    353.8 ppm   a_mu  -5025.0 ppm
   quarter Thomson cross-section        a = E_out/mc^2 (j=0)                       a_e   -380.3 ppm   a_mu  -1976.0 ppm
   quarter Thomson cross-section        spin mass excludes E_out (j=-1, Aspden)    a_e    779.8 ppm   a_mu   -813.5 ppm
   classical radius                     a = E_out/mc^2 (j=0)                       a_e   -805.4 ppm   a_mu  -1550.0 ppm
   constants j+k span 5.27; Aspden's lands 0.00445 from the target, next best 0.0284
   chance that one of 21 such constants lands this close to a random target in that span: 0.035

4. second-order coefficient of (alpha/pi)^2: Aspden -(4/sqrt3 - 1)/4 = -0.32735, QED -0.328479
   muon-electron difference / (alpha/pi)^2: measured 1.16181; Aspden 1.1574 (2/sqrt3 = 1.1547 at leading order); QED leading term (1/3)ln(m_mu/m_e) - 25/36 = 1.08276
   simple numbers near the measured value: 2/sqrt3 = 1.1547 (-0.61%), 7/6 = 1.1667 (0.42%), pi/e = 1.1557 (-0.52%)
5. muon, footnote form with 4/sqrt3               : a_mu = 0.001165874147 (-39.93 ppm)
5. muon, footnote form with 4 sqrt3 (as printed)  : a_mu = 0.001172052325 (5259.0 ppm)
