Homemade front torque boxes

I am not sure I understand your question. There are 2 half circles at the bottom to allow any water to drain. I was going to use the seam sealer to go over the joints on the entire underside of the car as my motor an transmission is out getting rebuilt. I am going to "clean up" the areas between the stitch welds, minus the drain holes.
I've had the car for 10 plus years now and washed it maybe a handful of times and never driven it in the rain and sits in a heated shop.