All three have good hardware kits for a 74 duster with through the k-member sway bars.
Hotchkis is tubular/hollow, has nice stamped bar ends with formed cups, straight as it goes through the k-member.
Hellwig has tubular or solid. Bent through kmember for extra clearance. Bolt sway bar attachment hardware
Firm Feel offers solid. I think you can order tubular. Bent in middle and bolt in hardware.
Up to you to compare price.