Want to pick up soraka as a second support but need help

So I am a top/jungle main however I would like to be more prepared in case of auto fill. Right now I have exactly one support I am competent with which is sion, and while I am quite good at sion support, I would like to have at least one more under my belt.

Which brings me to soraka. She seems like the near polar opposite of Sion and so would fill the opposite niche that he does. So I ask you, masters of the banana goat, what can you tell me about this champ,

note that I would like to avoid spending a fortune worth of ip on the champ so if you could point me towards not a perfectly efficient rune page but a passing one without things like mana regen and such. Thank you so much for any help you can give