I absolutely love this name for a girl, but I'm unsure on the spelling. I'm not keen on the 'er' part as I don't think it looks very nice on paper and could lead to people emphasising that part and saying tee-ERNIE which I really don't like.
I was considering spelling it Tianey, with Tia as a nn, and I've also seen it spelt Tianie, but I'm a bit unsure as I've heard it can be a boys' name? I spotted it on a baby name website as a girls' name though.
Any opinons, suggestions or advice appreciated!