Figured I'd ditch that old thread.
Catch-up: I damaged my spoiler and then realized this was an opportunity to remove it completely.
OK I visited Austin Bolt Company and the guy there was super cool and set me up with four stainless steel bolts (to fill the smaller-than-dime-size holes) and locking nuts for the inside and four sets of sealed washers (washers that have rubber on one side). I didn't bother painting the bolt tops because I actually like the look of the four stainless steel bolts. And wow I really like the look of the car better now. And if/when I sell this car, if they want a spoiler put back on, it would be very easy to remove these "plugs". I haven't tested their water-tightness yet but I'm confident they are quite water-tight.
Cost in time and money: Austin Bolt Company is 2 miles from my house and I spent about 15 minutes there as the guy invited me back into their warehouse to walk with him to get just the right bolts. Total cost for the bolts, nuts, and washers: $2.00! I got home and it took me about 10 minutes to install all four sets.