If you use 1/56 scale as compatible with 28mm figures, the dimensions are:
L = 3.4 inches = 86 mm (with tail)
W = 1.2 inches = 30mm
H = 1.5 inches = 38mm
If 1/48 scale:
L = 4.0 inches = 102 mm (with tail)
W = 1.4 inches = 36mm
H = 1.75 inches = 44mm
So either would work.