You can do the jackstand test to get close but a friend of mine used to hit his radius arms when he got twisted up. (Vic)
He also had a problem rubbing on the radius arms and catching a tire lug & binding up which breaks the joint. I don't know if it is across the board but his arms were a bit of an "I" shape which gave a nice lip for the tire to catch. He ended up welding a mini skid plate onto the arms where the tire would catch and he never broke a joint again.