Oh yeah, I agree fully. I'm not saying that spring rates should be used to determine your ride. They are a small part of how a jeep will ride. Shocks by far play a bigger role in ride and handling. I also agree that a custom tuner can work with any spring rate to dial in what they are looking for.
I was just saying the dual rate springs work well for carrying a load. I did mention handling advantages, but I thought I was clear that could not be validated. Its mostly theory used by some spring manufacturers. Because this can not be confirmed or denied short of taking a Jeep to a skid pad, I should not have mentioned it.
I also should have been more specific when I talked about how the dual rate spring is better at carrying a load. I was referring to carrying loads that vary in weight from weekend to weekday. In that situation, I think a dual rate spring is a good alternative to using airbags. If your Jeep weight remains mostly constant, I don't think a dual rate spring has any advantage. Get the coil that carries your weight and get the best shocks you can afford.
To be clear, I agree with mrblaine that shocks can make or break how a Jeep rides and handles. The coils simply carry the weight. I even agree that Bilstien have some small event harshness. But I think that slight hashness will bother some people more than others. For my needs, which are mostly highway driving with occasional trips were I am carrying a heavy load, I prefer how the Bilstien handle. I also really like how the dual rate coils allow me to pile in more weight for a long trip. So I choose that compromise. If I was doing more offroad oriented rock crawling, I would likely prefer a different shock.
I think part of the issue when dealing with coils and shocks is that its easy for people get the mistaken idea that changing coils will transform the way their Jeep handles. It will not. Any changes made by the coils alone will be very subtle if at all. And some of that may be attributed to other factors as well. The shocks will have a greater effect on ride and handling. I think another part of shock/coil conversation that gets into a heated disucssion is when we start mixing in over the counter shocks with custom tuned. No question that a custom tuned shock can be tuned to perform precisely as intended without knowing the coil rate. But over the counter shocks cover a broad array of performance parameters. I don't think there is a one size fits all when it comes to choosing over the counter shocks. I was simply trying describe how the liner/digressive design of one shock may differ in performance from a more progressive design of another shock. My apologies if I misrepresented the role that spring rates play in tuning a shock or tuning a Jeeps handling.