I have a 400 made the base out of wood. I enclosed the bottom of the stand bottom with a 3/4” ply wood and the bottom sides using 2x8 and then siliconed where it all met. All the corners and crevices to make it like a catch pool. I believe on the calculator it’s estimated to catch about 100 gallons before it overflows.
For me that’s piece of mind, unless the DT cracks, I won’t have water on the floor god willing. Knock on wood.
Just an idea but I’m sure other good ideas will show