It doesn’t have to be friction alone- mine has ties between the lower hole where the radius arm fits and the damper mounting. If they are going to move it tends to be outwards so a bit of 16SWG sheet in tension has worked for over 40 years. On the other hand, another car I have doesn’t have ties and that’s been ok for a similar length of time. Depends if you wear belts with your braces.
Alan Fairless