Hackintosh inside of an iMac 7,1: Best Motherboard Size?

Hello!

I'm new to the whole Hackintosh thing so if you've got any advice for me, please let me know! :)

So my school threw out old iMac 7,1s and i secured one for myself. It only has a core2 duo and 2GBs of RAM. I wondered if i could build a Hackintosh inside the iMac running the newest possible macOS.

I can get an i7 6700K for pretty cheap so it would be great if someone can recommend me an z170 Board that fits the iMac. Or maybe a whole other CPU generation if the i7 6700K isn't so good for this kind of thing, like i said i'm really new to Hackintosh's.