George B
¯\_(ツ)_/¯
After lowering, I did my alignment with a string pulled tightly between two heavy jack stands and a stainless steel metric ruler. The only thing I don't know is my caster. I know it's positive and probably a good bit more than what's specified for these rigs. Steering wheel is straight (it REALLY bothers me if it's not), it tracks straight, is not darty, steering isn't heavy, return-to-center feels like stock, etc. When I first finished the drop, the wheel was about 30 degrees slanted and steering was twitchy. I eventually got it to where I could fine-tune the steering wheel's straightness by turning the wheels to each lock and reaching the tie rods. I'd test drive, pull over into a parking lot, adjust, test drive, etc.
My point is that it's not so difficult once you have a handle on it all. Loose/floaty steering can be slack in the system or improper alignment. It sounds like you may have the slack ruled out unless something you replaced is defective. Maybe you don't have enough toe-in?
Are you a big ol' boy? I've seen a customer bring his car back multiple times because it kept pulling. On the rack, the numbers were spot on and centered within the spec'ed ranges. The alignment tech asked to speak to the customer, and when the customer was approaching, the tech suddenly changed his mind about speaking to him and just said he wanted the customer in the car while he did the alignment. The customer was a really large dude and the car was some small thing (Corolla maybe?). With the guy in the car, the suspension would squat enough to throw the alignment off and cause the pull. The car was aligned and it never returned after that except for oil changes and rotations.
sorry but LOL!