Our "Experience Team" is made up of myself (design) and two front-end developers, and we oversee all user-facing features with the remainder of the dev team (~20) focused on the foundation of the product, admin features, etc.

Our team uses Basecamp for requirements and Marvel for hi-fi mocks, and these are developed off of up until the devs are at the ~90% mark. Then, the developer and I get on a Zoom call (we're 100% remote) and do CSS/JS pairing to put the final polish on the product, tackle interactions, etc.

This process has helped a TON to save time, cut down on context switching, and ensure that the product is consistent & polished, regardless of which dev is working on it.