Thanks for the update on recipe re the different types of genever. The old duff version plus vermouth Di Torino works really well. Brings out the maltiness versus vermouth fruit and depth brilliantly. Still wondering if some slight tweak might balance it even more?

Given that New York was originally a Dutch colonial town, then named New Amsterdam, it is little surprise that genever would have been the original 'gin' used in this cocktail.

Used old Simon, which isn’t particularly orange flavoured, but the result was nonetheless quite fruity - not to mention very complex, bittersweet and surprisingly herbal- used Dolin for both vermouths. Would love to try the maraschino version at some point too.

Not sure about this receipt. I felt the subtle (good quality) Dutch genever was overpowered by the orange Curacao.

For a lovely version with hints of vanilla, add 20 mL Licor 43 tothis recipe. We call it the Señor Martinez.

Warning: do you NOT use Old Duff Genever, which I did first thing me. In this recipe, it will totally overwhelm the taste. Use a more subtle, mellow old genever. I agree with Simon choose with care.

The genever gives this a really nice and interesting yeasty breadth depth.

This is my favourite version of this cocktail. The genever adds a different taste more to what the original may have tasted.
We will never really know about the original cocktail. According to Wikipedia the actual origin of this cocktail is not known. https://en.wikipedia.org/wiki/Martinez_(cocktail). Since there are many versions here, I suggest trying the all and keeping the one (or ones) you like the best.