Velvia was my first film choice for pro golf coverage (probably exposed around 200,000 frames) - most sports agencies used Velvia in daylight - some routinely pushed to 80 ISO. For my E6 plot Lab 40 ISO was not over exposure, it was just right with no highlights blown for repro. Fuji's 50 ISO rating was bunkum, it was already heavily over-saturated with deep shadows and grey whites at 40 ISO - not to say that 50-64 should not be used for effect.
Scanning my library of golf images over the past 12 years using Imacon and Nikon scanners I now wish I had rated Velvia at 32 ISO as the highlights have been no where near clipping at 40 ISO. In fact with hindsight it would have been better to use Provia as its shadows are slightly kinder for scanning. However at the time Provia, in comparison to Velvia, just didn't pop on the lightbox; art directors in my industry craved for velvia for its saturated colours, especially for recording golf course greens.
Don't restrict yourself to shooting Velvia in soft light, experiment to take advantage of Velvias high contrast by using it in the harshest light; it will turn shaded backgrounds to gorgeous darker tones or black. There is a limited window of light to light subjects with no or little shadow under full sunlight and yet render uninteresting backgrounds very dark or black. After the golden hour when the sun is past its best, backlighting is normally adopted so that faces, especially under hats, can be clearly seen.
I attach a few basic examples of shooting Velvia in full sunlight.