For those to whom these things matter the construction of a Martini is, I think, as individually definite as the choice of the correct Tie for the man about town!
As with so many of the simplest things in life it's remarkably easy to get it wrong. Having found my way to my own version I'm now unable to order a Martini when out drinking.
8 parts Berry's No3 Gin (Frozen)
1 part Cocchi Americano
Stirred with ice, Strained/Poured into a Martini glass, from the freezer, with Lemon zested over it. Perfection.