Either way will work. Because they are essentially equivalent. Not surprisingly watermelons take up a lot of water and the drip system will be more forgiving than the ebb n flow.

I think Buckets of CoCo will be your best choice since it can hold more water.

You can maintain it more easily, but if you really want to to do Hydro I would go for an aeroponic system for watermelon because you will get better results.

Hope that helps and good luck!

So i decided on ebb and flow. I put the plants in the system today. Unfortunately I snapped a couple seedlings in half while fiddling with lights and what not. So time to plant a couple more.