that's the best answer I've heard.2 pieces of angle turned out would work well
I would be tempted to find some 3x3x1/4 angle and use two pieces with the legs going away from the pins. You could even add braces from one leg to another to prevent them from spreading under load. Much easier to find angle in that size than channel.
2 pieces of angle turned out would work well
That is the way I built the brush fork frame many years ago:that's the best answer I've heard.