I got a .35 HVS2 yellow gold DBTY pendant from Tiffany about 2-3 weeks ago. I didn't see the need to go higher in terms of color or clarity as I could see no difference and the price point really jumped.
I have super sensitive skin, too, but no problem with the cutlet irritating my skin- at least yet. It does not flip, but I do sometimes have trouble centering it on my neck, if that makes sense (it tends to go either too far to the left or too far to the right). It takes a bit of adjusting.
Enjoy your new necklace!