The cucumber is suggested on the tag of a bottle of Hendricks. In a Hendricks Gin and tonic I usually use a couple of slices of cucumber and slightly muddle it. I haven't tried it with Tanq10, but I imagine it would be good -- probably with most any gin, actually.
The Hendrick's flavorings though seem to suggest cucumber all by itself...
It doesn't work with Bombay for me. Make's it taste metallic.