a friend and me just triangulated some mazda arms for a guy, using the unusual fabrication kit. the bolt appears to be the same size as toyota. we used 3/4" all thread, but it was a bit to big to fit through the control arm holes. so we put the all thread in a piece of angle iron and rotated it steadily while using a flap wheel to make it smaller. it just needed the tips of the threads shaved to fit. it still allowed the nuts to fit and tighten. for the bushing we just removed the steel inner sleeve since the bushing is 3/4" i.d., and tacked it all together. then removed the bushings for final welding.
here are some pics
and for what its worth, we set the distance from the front side of the control arm, to the back of the rubber bushing at 9 3/4". hope this helps