I like the tall, cylindrical hop spiders and I wonder if you recirculated the kettle for a while with the return going into the inside of the hop spider if you'd deposit most of the trub into the hop spider. (Use the hops as a filter like in a hop back.) -I'm using a giant stainless "tea ball" or I'd try this myself.
The other solution that seems pretty obvious if you're going to whirlpool, is to just cut and rebend your dip tube so that it pulls wort from the OUTSIDE bottom of the kettle instead of the inside bottom. (Like in a commercial whirlpool vessel.)