Well, I know im gonna get screwed for not doing the "correct" way, but...
The old seal on mine was literally cut in half. So when I removed the old filler neck the seal came out together. Then before installation, I lubricated the ID and OD of the new seal with rubber grease (ATF will do fine) and put it back in. I didn't have to drop the tank... (will do that once I have more time to remove the black paint). Oh, I have small "Asian" hands, so I can squeeze the new seal in through the hole in the trunk where the filler neck goes in without any problem.