Ok, these figures are from the S2B but should be appropriate for any one in the series.
In your aircraft.cfg you will see the section called 'contact points':
[contact_points]
max_number_of_points = 7
point.0 = 1, -13, 0, -2.3, 8000.000, 0.000, 0.238, 60.000, 0.300, 2.5, 0.600, 0.000, 0.000, 0.000, 0.000, 0.000
point.1 = 1, 1.889, -3, -5.15, 1600, 1, 0.709, 0, 0.323, 2.1, 0.8, 0, 0, 2, 0, 0
point.2 = 1, 1.889, 3, -5.15, 1600, 1, 0.709, 0, 0.323, 2.1, 0.8, 0, 0, 3, 0, 0
point.3 = 2, 5.5, 0, -1, 2100, 0, 0, 0, 0, 0, 0, 0, 0, 0
point.4 = 2, -1.6, 9.5, -2, 2100, 0, 0, 0, 0, 0, 0, 0, 0, 0
point.5 = 2, -1.6, -9.5, -2, 2100, 0, 0, 0, 0, 0, 0, 0, 0, 0
point.6 = 2, -10, 0, 3, 2100, 0, 0, 0, 0, 0, 0, 0, 0, 0
You want to concentrate on points 1 and 2 (if your tailwheel seems a bit sunken that is point 0). Change the -5.15 to -5.3.
Hope this helps