Length = 34.4 +/- 0.05 cm
Gap = 12.709, 12.716, 12.699.  Mean = 12.708 +/- 0.0085 cm
Distance from Stage 1 to magnet = 38.3 cm 
Total Wire Length  = 118.5 cm 

B Field    Current   at magnet center
  (T)         (A)
0.038382    12.00570
0.038394    12.00605
0.038370    12.00635