Ok, for what it's worth, here's the official write-up on what I did.
First thing I did was pull up the carpet and pad so that I had a clear place to work, and guess what I found. I'm assuming that this is the build sheet people have been talking about. I stuck it in plastic and will probably just stick it back under the pad next time I think about it, since I'll lose it otherwise.
The rear molding is still in place because I stripped the head of one of the screws, and I didn't feel like getting sidetracked; the carpet was loose, so I did the job and took care of the screw later.
I chose where the holes would be. I decided to center the tire on the rearward bolt of the backseat catch, because that left me room for a 38" or 40" tire without overhang in front, should I decide to move up in the future. I decided not to put the tie-downs through the seat bracket because I didn't feel like chiseling off the bolt, and in trying to plan things "perfectly," I kept running into things undernerneath, so I just chose a spot that seemed like it would be somewhat supported (the end of the groove) and measured back an equal amount past the bolt I had chosen for my center, which put me at 16" between the two.
Next, I drilled the holes.
Going with the principle that any sealant is better than no sealant, I used some calking that I had left over from a bathroom remodel. Since I was on my own, I had to figure out how to hold the bolts while I was tightening up the nuts underneath. A hint here: leave the bar through both loops and tighten both at the same time. On the first side, I did one and then the other, which swung the bar over on the second one, so I took the bar out of the first loop and just braced it against the wall; as I tightened the second one, I kinda tweaked the floor a little (and the angle of the bolt. On the second side, I left everything in place and tightened them together, and it came out perfect.
Put some calk right around the hole...
...and a thick bead on the washer - hey, calk's cheap.
Here it is tightened down.
And here you can see how it's going to work.
Other side, all done.
And a close up (after I semi-cleaned it up). You can see that the piece doesn't come up any higher than the top of the bed - no bump in the carpet.
Now on to making the tie-downs acceptably accessible.
I carefully measured out where the tie-downs were, and trimed out the strips of cardboard to allow the mat to still settle into the grooves of the bed. The strips are doubled up, so I put some staples through to hold them in place - regular staples; I think a staple gun would be too long (ouch).
This is where the height of the tie-downs comes into play; they match the height of the cardboard strips, so the carpet is still supported. :thumbup Yeah, it's petty, but I thought it was cool.
The hole in the tie-down was too small for the pen I had, so when I put the mat back in place to mark it, I ran a small drill up from the bottom, just to mark the pad, then pulled it back out and used a bigger bit to cut the access hole.
Here, you can see where I cut and stapled the cardboard.
Three of the holes were perfect; one was a little off, so I did some cutting.
While I was cutting that one, it occured to me that the plugs (which are just barely taller than the fitting) were going to need some room, so I ended up trimming all of them a bit larger. After I was finished, I decided that I probably won't use the plugs anyway; instead, I'll find a bolt that will take up all the threads, since the plugs are only 3/4" and I'll want the threads clean when I put the eye-bolts in.
Now I had to put the holes in the carpet. I set that piece of wood in the other pic on top of the holes and weighted it down, then drilled up from underneath. Once I had a small hole drilled through the carpet, I had to figure out how to make it bigger, and not have it fraying. I figured heat was the best way to do both.
Yes, that's a junk bit.
and there ya go! :thumbup
Now I just gotta get a couple of straps, and it'll be secure.
Done.