Go by a Regal dealership and look at the sundeck models they have. The 25 2 33 all have a swim platform that that lowers as much as a foot the water below the fixed platform. I am sure they would share the manufacturer.
I added a SeaLift hydraulic platform, on my 480 Sedan I absolutely love it. After 3 years there were some easily repaired issues with the hydraulic lines. We now have Stainless lines for the system so I don't expect any more problems. The manufacturer gave wonderful phone support.
