Yeah, once you change the name of the first downgrade file it will flash automatically. After that file flashes you need to delete it off the card and then put the upgrade one on. Go slow, follow step by step, copy and paste the commands and did I say go slow? There have been zero bricks according to jcase as of now on IRC. Make sure you have IRC loaded and ready in case you have an urgent question. I'll be back here around 7:30 or so if you need any help.. PM me. I'll mostly be on xda and irc.
If you're going to do this, and I'm not by any means suggesting you do, don't panic no matter what happens. I've seen a few folks copying the files in the wrong order, md5 that doesn't match, adb disconnecting. That happened to me and I needed to reenable usb debugging and unplug and replug it in. Then adb found it again. Anyway, best of luck. I think you'll be just fine whatever you decide to do.