I find it hard to believe that the control arm is too short. If that assertion is true, then the tech should back it up with Steering Axis Inclination measurements. They did measure SAI... right?
The funny thing is, there’s more than one thread here where an alignment tech told someone their control arm was too short. I’m not sure what they’re teaching these techs, but I’m pretty sure “your control arm is too short” is slang for “I can’t get the machine to turn the little box on the monitor green”.
But it doesn’t help that the machine is trying to get them to dial in +.5° of camber and -1° caster so your car drives like a shopping cart with radials on it. Especially when you have aftermarket UCA’s that are designed so you can have -.5° camber and +4° caster.