I have tried cucumber gin and while it would not be a drink of preference, it does work in a bizarre way My own choice for gin would be Bombay sapphire which I use in G&T and Martini's alike. Bombay has just enough of that juniper taste to come through a strong tonic, which is what you want ( only ever Indian Tonic Water ) I would use 2/1 in favour of tonic over ice which has been cracked with lemon or lime juice and the glass should be cold if not frozen. Interestingly enough, where I live in London is the site for many of the old gin producers ( Gordons, Gilbeys, Booths ) and consequently many of the pubs round there are old "gin palaces" with fantastic Victorian furnishings. The best of these is The Eagle ( on The City Road ) which while not being great as pubs go is stunning inside and a piece of history being part of the origins of Pop Goes The weasel.