I’d go with what the Oakley folks said. I live in the Northwest, in a very exposed area. Anything over 20% would be way to bright for me. 16% is pretty much perfect for me most days. And I have a 10% (Black Iridium) that I use a lot of the time too and it’s fine. I do think the Iridium coating makes a difference. If you can find the charts that some Oakley dealers have, you can actually see what wavelengths the different lenses transmit. It’s quite remarkable the differences.
I like a lens that boosts contrast. So based on that, I’d probably go with the G30. BUT, some people like a lens that just sort of shows what’s “normal” without distorting colors (like the Black Iridium). I prefer the contrast enhancement of the +Red to the “truer” color of the black lenses. But that’s totally personal. The Slate Iridium is a lighter version of the black. So it’ll be similar to what I would see if I lived somewhere where the sun was less bright (like the Northeast).
The other thing to consider is when you ride the most. If you ride most often in the mornings/evenings, then you’d want something different than someone who rides mostly in the middle of the day. If you are riding a lot later in the day, a 30% lens with more contrast might be better. The Iridium coating is nice if you live somewhere where the sun is bright and there is a lot of glare. That doesn’t sound like you.
It’s important to remember that you want a lens that works best for riding, because that’s when your vision is most important. The fact that they might not be great for going out with friends because you don’t want them to look orange is not really that important, IMO. I find that your eyes adjust as well, and that you won’t actually notice that everything looks “rose.” Rather, when you take the lenses off, you’ll notice that everything looks really blue (IIRC, from when I had similar lenses).