You will probably have got a wealth of responses from your research. Lumineers are a one of a group of products designed to mask colours in thin sections by using a fairly opaque masking component combined with pearlescent material to shimmer a little more and compensate for the flat colour normally achieved when you use opaques.

All things are relative so I cannot help on the specific suitability for you. My basic approach is to lighten the basic shade first using a dentist monitored tooth whitening system ( NB.grey shades are not the best starting colour /hues). Once this has stabilized, Veneers are normally suitable. If your dentist is happy with a system they will often get better results with what is familiar. A second opinion is a good thing if you have doubts. You need to be confident in your dentist, it should not be an issue to reaffirm your choice of dentist.