If you can find another bread tray ( so as not to ruin the present one )...you might cut out some of the plastic
cross hatchings in the bottom, still plenty of strength there and gives more room for soil to go through,
part 2...cut off one side of the upright sides. Planning for long hours of screening, undesirable things like twigs and stones can be 'swept ' off the screen without the need for actually picking them up and out.
Look very close at the black frame intop pic of mine,the one side is bolted UNDERNEATH the screen for that 'sweeping' effect...works good for me.
If thats Idahoe's professional opinion I'm never going rafting with him ......Maybe screen mesh bottoms is what they use on the tranquil Snake R in Idaho but it will never float the TX Guadalupe