For example:

ContourLayer.LabelTolerance = 8
ContourLayer.LabelLabelDist = 0.5
ContourLayer.LabelEdgeDist = 0.75
ContourLayer.LabelFormat.Type=srfLabFixed
ContourLayer.LabelFormat.NumDigits = 2
ContourLayer.OrientLabelsUphill = True
ContourLayer.LabelFont.Face = "Arial"
ContourLayer.LabelFont.Size = 8

See also the attached script ContourMap.bas, which can also be found in the \Samples\Scripts\ folder in the Surfer installation directory.

See here for instructions on how to edit the properties of contour map labels via the user interface in Surfer.

Updated November 1, 2018