Radian XT Mazda 3 RF successful install? (Bracing and tether question)

Me and my Radian and my Mazda are back asking yet another question:

I have tried to get a more upright angle on the Radian XT in my Mazda by following some of the tips on here--pushing down at the foot, holding the back up while installing. Currently when I pull at the belt path there's very little movement, with and without bracing and tether.

http://www.flickr.com/photos/90991238@N00/5634763143/in/photostream

I'd like to brace it on the front seat as well, since we get so much change in the angle when there's a tall heavy kid in it. I have it braced, but to get it against the top of the seat (rather than just pushing on the back) it is barely compressing the seat at the back part (by the kiddo's spine) only at the front part (by the kiddo's feet). In other words, putting it against the seat is doing a good bit of work on the upright angle. *Is this a problem?*

Here's a photo of the bracing from the front looking back:
http://www.flickr.com/photos/90991238@N00/5635348246/in/photostream/

And this is where it is significantly less compressed than it was previously, and even when it is un-braced:
http://www.flickr.com/photos/90991238@N00/5634765025/in/photostream/

This is for a 2 year 4 month 38ish lbs 37.5" tall 22" torso-ed giant chunk of love.

Thank you--I went to the car seat event two weeks ago and the tech wasn't willing to talk tether or bracing since he wasn't familiar with it and my Mazda manual didn't specifically say "please, brace and tether your Radian." (also I don't know how to insert photos, sorry!)

I found this in a Mazda 3 manual.

"Seating Children in a Child-Restraint System on the Front Passenger Seat:
If your vehicle is equipped with front passenger seat weight sensors, a front passenger
air bag deactivation indicator light is also equipped (page 2-29). Even with the front
passenger seat weight sensors, if you must use the front passenger seat for children,
seating a child in a child-restraint system on the front passenger seat under the
following conditions increases the danger of the front passenger air bag deploying
and could result in serious injury or death to the child.
l The total seated weight of the child with the child-restraint system on the front
passenger seat is approximately 30 kg (66 lb) or more.
l Luggage or other items are placed on the seat with the child in the child-restraint
system.
l A rear passenger or luggage push or pull down on the front passenger seatback.
l A rear passenger steps on the front passenger seat rails with the feet.
l Luggage or other items are placed on the seatback or hung on the head restraint.l The seat is washed.
l Liquids are spilled on the seat.
l The front passenger seat is moved backward, pushing into luggage or other items
placed behind it.
l The front passenger seatback contacts the rear seat.
l Luggage or other items are placed between the front passenger seat and driver seat.
l Any accessories which might increase the total seated weight on the front passenger
seat are attached to the front passenger seat.
The designated positions with seat belts on the rear seats are the safest places for
children. Always use seat belts and child restraints."

I would take from this that bracing is not allowed, just because it appears it could interfere with the airbag sensors. Does your manual read the same?

It does. I'm wanting to brace for the angle when there's no one in the front seat. Actually our light isn't going off at all, so no one even remotely small is going to sit there until we see someone about it anyway. With no bracing there's no space for a person anyway, so we're not losing a spot, and we're gaining a good toddler angle.