Yeah what Mino said about the blogging thread.
Also I believe you should go for UFO first. Raiko may not be particularly hard but her stage is very hard compared to a lot of other Extra Stages and because of that having the resources to beat her can be somewhat grueling. Also if you learn the ways of getting UFOs, you can grab a ton of bonuses easily. Here's a replay of mine with SanaeA on Normal, it was my first UFO 1cc. I don't even do well and by the time I get to Byakuren I was falling apart, but for the first 5 stages I think I did a decent job of showing you how you can grab #toomanylives.
Although I highly suggest memorizing what UFOs are given out when because I miss a lot of chances to get some free bombs. :V