I feel like Hnpickup is cheating though. But I'm glad you saw mine and too many features is a totally legit reason to not use it. In fact, sometimes you just want to make your own thing no matter what's out there.
You don't actually need hnpickup. Just remember to post in the morning or late evening PST.
Since we're here: I'm immediately put off from writeapp for two very simple reasons: 1) very cluttered homepage, everything is extremely verbose 2) requires sign-up (and no OAuth) before I can see anything.
Can you imagine github's homepage with a "Publish git repositories and make them available for co-workers and contributors to commit, track issues and send patches to" in big bold letters? You are in desperate need of better copy.
The actual app is nice, I prefer it's UI over the OP's. Other issues: Museo in the preview doesn't look that good, the options button is not working, and I can't figure out how to get a public link to a post.