If it works you may get a gallon or more of water. The condenser removes the water so you don't damage the pump. One boat shop in my area uses a small Shop-Vac for a vacuum pump. If you use one of these you do not need a condenser as they can handle water. I'm guessing the pump will need to run for a day or more.
Most foam is scored in blocks to allow bending.
The scores are often significant so that although the foam may not actually absorb water, there is significant volume between the blocks and a lot of surface area. On older boats you can see the outline of the squares by looking across the surface at a low angle. You should drill your holes along these channels. After you dry the core using either of the first two methods, fill the holes with epoxy and micro balloons, and then repaint the floor with a good non-skid paint. The extreme approach, but the only one guaranteed to work is what Peter Alarie did with Lindsay 7318.