SoCal - I will convert you into a 35 Kelly Girl if it's the last thing I do! You will never abandon your love for your 35 Birkin - you don't have to - they are such different bags and open up a whole new world, I promise......
Knowing your style, I'm guessing that you didn't immediately warm to the Kellys previously because you'd only tried on the smaller ones which, while absolutely lovely, give the bag a more ladylike, dainty vibe. The 35's put a new spin on the bag and IMO, give it a tiny bit of an edge. (Don't get me wrong, it's not THAT much of an edge - LOL - but it's enough to step it up a notch.)
I know you're tall - I'm only 5'0 and small - and I still love the 35's, both sellier and retourne. On you obviously, they won't look nearly as oversized as they do on me, but I don't think you'll ever regret adding one to your collection for variety.
I'm having a little trouble with color suggestions for you though, since you're a more neutral girl. (I'm all about color and my 35's are all somewhat bright.) But maybe a semi-neutral like Brique Vache Liegee, Noisette, Rouge H - maybe even Gold Togo. The 35's are somewhat harder to come by than 32's, but they're out there occasionally. Vache Liegee's are more likely to appear in sellier (I'm willing to bet that the Fuschia one you tried on in Madrid was retourne - they usually are), and you might like this size even better - selliers "appear" even larger. Togos, Clemence, Swift......these are more likely to show up in retourne - Chevre, Box show up in both. Ask your SA to call you if they get a 35 sellier in - you can try it on for size and then concentrate on what color and leather you want.