It's probably easier to do the masking and stuff in After Effects, resize and export as an MP4, then import into Photoshop to convert to a GIF. It's quite difficult doing GIFs in Photoshop but it seems to be the only way to do it properly without a tiny/low quality/watermarked GIF. I think there are some HTML5 things coming along which are similar to GIFs but have a much better quality:file size ratio. So far the only thing I know of doing it is Gfycat but you can't embed them in MacRumors and other sites yet, would be cool if a website such as Tumblr decided to convert all uploaded GIFs to this HTML5 thing at least I think it's HTML.
*The URLs in Gfycat are a bit silly IMO so I hope they change that