We installed a SeaWise davit 2 years ago. The system is custom built for your boat. You can have a look in the SeaWise website for the order form and see what information is needed. Stuart (owner of SeaWise) is personally involved in the design and build of your davit. He is accessible by phone and email to answer any questions. Excellent customer service.
We installed the davit ourselves. Challenging at times but with Stuart's guidance we were successful. The box of stainless parts and pieces weighs about 80 lbs. Everything is supplied except the glue for the pads that go on the inflatable. Cost at the time was $5800 Cdn. Can't comment on installation cost if you have to hire someone. We are extremely happy with the system and it was worth every penny and curse word during installation.
Our dinghy is a Highfield CL290, 9'6" aluminum bottom with a 9.9 4 stroke Tohatsu outboard. On a 43 foot boat you could certainly go larger and still utilize a SeaWise system.
If you ever see a used Seawise for sale(very rare) be cautious as they are custom made for the mothership, dinghy and outboard so parts may not work for your boat.
Great system and we would highly recommend it if it fits your budget. Your back will thank you.