doesn't need to be spooled like a turbo
Can't be spooled like a turbo, once your pulley sizes are fixed you're left with whatever stall speed your engine makes. If it won't launch, you need to turn it faster and reach serious boost within your stall speed, a looser converter, or re-purpose the engine for better lower end torque (earlier intake closing, more static CR).

AFAIK the biggest complaint to the ATI is that most brackets are nowhere near stiff enough. The attachment points are limited to the nose of the engine, but the wide span between the pulleys is bad. The brackets look big enough, but the force on them bends both pulleys forward. It's enough to slip and mis-align them. In some cases a simple doubler plate added to the mid-span (someone on Yellow Bullet said "I use a section of angle iron") by rivets, screws (welding not needed) helps a great deal. Remember: aluminum is only about 1/3 the stiffness of mild steel, strength is not the problem.