Choose the base and tip together. A defined French line needs enough contrast, while a softer version can use closer colours.
Separate colour from coverage
The base may need a particular degree of translucency. Check the actual product description and swatch instead of inferring coverage from a pale pink name.
Try a coloured tip
A red, blue or dark tip can use the same visual structure as a white French. Keep the tip width proportionate to the nail and compare a test swatch.