If you used verygreen's size-agnostic SD installer, it's just a matter of putting his uboot update (toward the bottom of
his OP) and the RC1 .zip on the boot partition of your SD card, then booting into recovery.
Of course, you should back up with ROM Manager and Titanium Back-up first. Most people are good to go after the above steps, with all their apps, settings and data in place. When I tried it back when the 7.1 beta first came out and I was still on SD, I was not most people :/ I had FCs and Wi-Fi drop-outs, and rather than trouble-shoot, I just migrated to eMMC, where 7.1 ran perfectly. Like I said, most people don't have issues, but there's always a chance when you're flashing that something will go wrong.