Good observations, paw. Personally, I'll always reach for the Prat dry for a martini. (And, I do think the Vya is better than the Eider, but I like the Eider, too.) Where the Vya really shines is the sweet for Manhattans, IMHO.
Your portion juggling according to type of gin/type of vermouth sounds spot on. I aim for 3-5 "drops" of Fee orange bitters per martini. I'm pretty regular about this. Not much of an impact if using either Vya or Eider though. But I think orange bitters enhance a martini made with Prat. A Manhattan without bitters is simply a bourbon & vermouth cocktail.
I generally drink the Punt Y Mes straight-on-the-rocks. However, the bartender at the Zuni Cafe turned me on to using it to replace the vermouth in sweet Manhattans. (But use only half as much Punt Y Mes in relation to the amount of sweet vermouth you usually use.) Now, the Antica Formula is a whole different story. Much more like a vermouth than Punt Y Mes. Seek out a bottle or two. The King Eider is very comparable to the Vya as far as quality. The Eider is a bit more herbal though.
Average is 5:1. (2.5 ounces of gin & 0.5 ounce of vermouth. Sometimes, I'll go wetter.) I think it's safe to assume that you have Fee Brothers orange bitters? (Their mint & peach bitters are interesting, too. But I use those for baking more than cocktails.)
Possibly. You see, I keep the gin in the freezer as well as the martini glasses & pint glasses for mixing. Take pint glass from freezer & add 4 ice cubes for one martini or 6 cubes for two martinis. Pour in vermouth (that's been in the fridge). Pour in gin. (Always jigger the vermouth & gin.) Add orange bitters. Stir as directed above. Strain, garnish, lift, quaff.
What would be the point of that? Oh, I know: "let's allow smoking in all the poor areas of Manhattan and not in the rich, tourist and business areas." Horrible idea. Sam, your new duties should have you busy with other threads. You've put in your time here. Move out, private! On the double!
With Sam, on the Vya. But Duckhorn's King Eider is worth it if you can find it. (And, I've seen King Eider more often than Vya but I've a good supplier for Vya.) Mid-range range: As Sam noted, Noilly Prat dry & Cinzano sweet. (But sometimes I'll pick up either Noilly Prat or Cinzano in both sweet & dry when there are sales.) Cheap brands: As Sam, I don't bother. This summer, I'm also home-stocking--not so much vermouths as aperitifs--the following: Dubonnet rouge (French origin only as the American stuff is too sweet for my taste) Lillet blonde Cinzano Biano (nice with a lemon twist) St. Raphael red & white Carpano Punt Y Mes Carpano Antica Formula I think that's all.
Depends on how long you stir. I tend to stir approximately 30-40 seconds for one to two martinis. I get the proper dilution--for me--*and* a very chilled martini.
And to answer the original question . . . I try to keep two bottles of gin in the freezer: either Bombay (regular, not the vodka clone) or Beefeater's and Plymouth. I'm slowly coming to the notion that I should pare down to just a bottle of Plymouth. (Based on taste rather than lack of freezer volume.)
I note that question as it's quite relevant to considering & comparing gin flavors. I've noted the following on a different thread & I'll note it again . . . Sapphire was born when Stoli USA--which distributes Bombay in the States--wanted to increase its gin sales. So, Stoli USA approached Bombay & basically said, "We can sell more of your gin but you need to make it taste more like vodka." Thus, Bombay created Sapphire. When broadly comparing gins, I tend to begin with two huge categories: gin that's meant to taste like gin & "gin" that's intended to taste (? ) more like vodka. FWIW.