Did this today
Here is a couple more tips that I didn't see:
1) Don't touch headlight bulb. Oil from your hand would cause it overheat later.
2) I used a couple of flat screwdrivers instead of the knife. By nudging those in the clips, I can open up the housing along the longitude (start from one end and go the other). Requires some muscle though, since the sealant is like A LOT duct tape goo.
3) If you overspray the reflector, and they become too dark, use brake cleaner to remove all the paint, and retry :-)
4) Dont assemble lights until you got both of them done. So you can compare the color shades
5) Clean up the inside of the clear plastic before putting everything back together. Fingerprints on the inside would really suck :-P
6) Took me the whole afternoon and part of the evening (4-5 hrs).