I've decided to OTP Gwen on a new account. I don't play top. Any advice welcome!

Hello people! I'm a peak Diamond, currently Emeraldish ADC main. I've played since beta, and although I've dabbled here and there, I've never enjoyed top. I want to learn more about the role to better round myself out, and the few times I've played Gwen, she has fit like a glove. I'm 90% micro and 10% macro as a player, and I feel like there is so much skill expression on her that she really resonates with me. Open to any and all advice.

1. I main ADC/mid/supp/jung/top in that order. Should I go top/mid with Gwen? Top/jungle?

2. Her build order seems extremely dynamic given the patch. Besides looking at lolalytics, what are some items you buy that usually aren't listed as often bought?

Thank you!