I have been lurking on here for a couple of weeks, reading and re-reading.
Purchased an ATT SG2S in November 2011. It came with KH7. I did not root originally and used OTA update to KK6. My phone was fine except for the horrible battery life. I got maybe 12-14 hours out of it. My primary goal in rooting and updating the kernel / ROM was to improve battery life.
I followed the steps documented in the original post.
1 - confirmed no triangle (none there, no suprise since it was bone stock)
2c - rooted no problem. Flash took about 4-5 minutes.
3a - updated to Entropy's March 7 daily driver kernel -- added CWM. Took about 30 seconds to install.
4 - used CWM to install UnNamed 2.2.1. Took about 5 minutes.
After using my phone like this for a couple of days, the improvement in battery life is significant. My phone has been on battery for 28 hours and I have 9% battery remaining. This is with what I would call normal, but light usage (couple of phone calls, checking email a few times a day, handful of txts).
Huge thanks to this community for helping me understand the process. I hope to make some useful contributions in the coming weeks.