[kris_wayton]

The chart doesn't seem to account for the profiles that only have a slot on 1 or 2 sides versus all 4. I would guess those are quite a bit stronger. Like this one: https://8020.net/media/catalog/product/cache/9208ae76a38c408...

Edit: Their calculator shows the same exact deflection with the same weight, so maybe not, though that seems odd to me. https://8020.net/deflection-calculator