Next step mostly complete. This weekend I got the harness mounts installed. As usual, I took far longer than it probably ought to, but elected to take my time and make sure I did the job as right as I could. I ended up using SoundGuyDave's response to a question I asked regarding this from a while ago and it worked out well (here:
http://s197forum.com/forum/showpost.php?p=1977581&postcount=462). I ended up mounting four forged eyebolts behind the stock seat mounts, each will be used to attach a lap belt end and one of the anti-sub strap ends (fed through the seat joint).
Measuring, re-measuring, re-re-measuring. The first proposed location ended up directly on top of the air deflector stud underneath the car, so I had to adjust. This is where some extra time & thought paid off later, making sure that only one hole got poked in the car exactly where I needed it for each bolt.
Not lots to see yet. Pilot holes poked, lots of sound deadening goop from Ford.
Outer mount point driver's side. Scraped the goop & saw it was still not a smooth surface. Once everything got torqued down, the bolt ended up relatively straight--and I don't mind the little bit of doubled-up sheetmetal sandwiched there.
Hole drilled & test-fit, passenger side.
Trimmed fender washers for inner mounts, underside. Doubled-up to add some strength, and jammed under Boss302 side exhaust brackets.
Driver's side outer mount backing plate test fit.
Driver's side bolts mounted.
Outer passenger side backing plate clearanced & test fit.
Outer driver's side mounted.
Inner driver's side mounted. I had to take a pair of pliers & bend the tab out of the way (it was parallel to the floor pan--now is a nice buffer for the bolt).
Driver's side air deflector with clearance hole drilled & mounted.
Potatocam shot of what you see with the carpet back in place.
And a close-up of one bolt.