The kit I was offering uses your OEM seat as the foundation. It's all about the foam, how its shaped and its density. The tall kawi seat is an improvement over stock but its still uses the same foam density as the stock one (just more of it), so its hard. I have even added a thin layer of foam over the tall kawi seat and still didn't like it. This is how my seat came about because I wanted a simple/quick solution but nothing was available. The Luimoto looks great but that don't change the angle...its just an even layer of (thin) foam. The Corbin is expensive (understandable) but don't like how they shaped the foam. When I first got my Z, Corbin didn't offer anything so I went on a long test stage in making different seat options. By the time I finished, I learned a heck of a lot (from the earlier failures).
FWIW: Yesterday, I went on a little trip to celebrate its 10K mile mark. Three fuel stops and 11 hours on bike - While the last 3 hours were tough, NO WAY would I have been able to complete that on either of the two kawi seats.