Here you go - showing how to lift a small boat with a lifting beam and single davit, in a storm nonetheless.
Pretty sure that these skiffs weigh a lot more than your rig, took about 30 minutes to load six of them in the rain.
Problem using two davits, is coordinating the use of both of them together. I do a LOT of rigging on a pretty much career long basis, unless you have help ( and sounds like sometimes you don't ), running between two sets of controls, or keeping two sets coordinated, can be a hassle. A single 15,000# davit should pick your boat up full of water no problem. Then just build a simple cradle on land to leave the boat on, problem solved.