walkthru, cut or nocut?

[tigeman1]

I have a 02 22ir and making a custom ballast system. I need to know if there is space below the walkthru to make a hole with a hatch, trying to conceal 500 to 600 pounds up front. I don't think there is enough space under the front seats, so I thought this way could work instead of adding leadbars or portable hefer's Thanks for any insight