The constraint on the dinghy is likely not to be the size of the dinghy, but it's weight. The Davits will be designed for a specific working load, and may also have other descriptors such as safe working load or maximum working load.
Max load, implies that if you overload it will fail immediately
safe working load is not a continuous loading, and will effect the life of the system, but should not be an immediate problem.
I designed my davit system so that one davit was specified capabe of continuous use above the total weight of the dinghy.
When it is bouncing around on the davit when being lifted out of the water
, or in rough seas and inadequately secured, there will be a significant snatch load that will be multiply the working load.
When it is raining, the dinghy will probably top up with water
, and if you have forgottent the drain plug
(again), then the water load can be considerable.