How do you remove the center tail reflector?

Remove the trunk liner and then remove 3 bolts, 10mm. give it a slight pull forward to release 2 clips.

Out of curiosity, what are you up to (if you don't mind me asking)??

As PontiacDad'* post indicates, it'* pretty straight forward. You need to be especially careful so as not to damage the plastic clips near the points beside the reverse lights. These aren't difficult to break. You can't buy them individually (I can't begin to tell you how bitterly I complained to GM over this). If they are damaged, you can end up with another path for water to get into your trunk (and we certainly have enough as it is). I searched and searched to find a used panel just for clips and not one had some that were any good. This means purchasing a new panel at $300.00 CDN+. If you don't absolutely have to remove it, I don't recommend it.

Haha I'm clearing the tails, which I proudly can say I did successfully.

What kind of bulb should I use to replace them after they're cleared?

You can buy silver bulbs that flash orange but some of us have just dusted orange bulbs with silver paint, works good too.