Question Radian XT Mazda 3 RF tether successful install?

I wanted to post photos here before I add to the successful install thread, which I think has no Mazda 3s in it. This is a Radian XT, DOM 12/2008, so it goes RF to 40 lbs (but not 45, boo!). It's behind the passenger seat: the other driver in the family is 6'9" so it can't fit in the middle. I tethered it to the outside seat track. I thought inside was a better choice (after reading around on here and about ketchupqueen's accident) but there's a piece of plastic in the way that I'm unclear on the smartness of moving. I had it checked today with a technician who said he couldn't officially help me with the RF tether because it wasn't specifically allowed in the Mazda manual and he was suspicious of RF tethers in general (though he also said he didn't know about RF tethers and would have to read up on it to understand the theory).

My specific questions are: is it tethered properly? Is a tether outside better than no tether at all? Finally: if this is a good RF tether, would I be doing the same thing with a Britax Multi-Tech or Two-Way? My 2y3month son is pushing 40 lbs and I'm considering skipping over the Radian XTSL to a Swedish seat so he can get to age 4 RF.

http://www.flickr.com/photos/90991238@N00/5603582815/in/photostream/

http://www.flickr.com/photos/90991238@N00/5604166594/in/photostream/

You can pop the plastic off. Sometimes you need to remove a screw, but often it just pops off. It's just there to make it look pretty, and so someone doesn't stub their toe on the rough metal.

Swedish seats require dual tethering. So you'd do both inner and outer.

It looks good. I normally go for the inner leg, but I've done the outer leg if I can't get the inner to work.

Wendy