Funny that you say this and thank you. I always feel like the crazy person, when I point out that certain products here in the US, even if labeled as such/identical, have nothing to do with the European version of such product. But rather being produced/catered to the American palette or as I call it americanized, even if it’s the same brand.
Nothing wrong with that, but gets me always excited for nothing, because it’s such disappointment at the end.
I agree with you that fage, does taste close to traditional Greek yogurt but it’s lacking the sour. Don’t get me wrong, while it has that in comparison to other brands, just not enough, which you seem to balance out with sour cream?
Anyways, I use Bulgarian yogurt, for me it’s much more authentic even so it shouldn’t but it is, and if I want it thicker, I’ll add cottage cheese. Give it a try one day, especially if you are low carbing 
Sorry for that long intro, but it’s vape related, because just like mentioned, that’s what Greek yogurt is. It’s not creamy thick over sugared yogurt, that’s sold here as Greek yoghurt.
So with that in mind, that’s how I build my yogurt vapes and just like Leticia, my first go too is (TPA) Greek yogurt. It’s the right sourness right off the bottle, so higher you go in percentage more sour you get, to even the point where it turns into real cottage cheese lol don’t want to push it up there.
I found that it doesn’t play well with other creams, that are dairy prominent. For example milk, if you hate yourself go mix that, you’ll see what I mean
If paired with a very buytric acid flavor, you will know what vaping vomit really tastes like.
But paired with creamier or richer flavors, that are not very dairy rich in vaping (examples: marshmallows, mascarpone, cream cheese, other yogurt, some ice creams, some sweet creams, some custard or even some bakeries and fruits depending on brand - think outside the box and test different combos) can result in amazing and authentic Greek yogurt vapes, rather than creamy children yogurt lol.
I hope this helps you guys a little, when trying to build a good yoghurt, which is not the simplest thing to do imo.
I mostly start with (tpa) Greek yogurt, (wf) mascarpone, (used to use a cheesecake for that, before this got released), (hs) Italian Cream as base and the decide if I want plain, fryity, nutty, creamy and what not.
Because by itself (tpa) Greek yogurt tastes just like Bulgarian yogurt in real food, and if course it does, same bacteria etc. But just like Bulgarian yogurt, tpa’s version is not as thick as Greek yogurt, hence adding the other stuff helps imo.
I could go on because I love yoghurt vapes, but it’s already long comment, so I leave it at that.