I have the usual Rubbermaid 10 gallon MLT with 12" false bottom and on my first mash I open the valve to nothing. Dump the contents into a pot, clear it up (lot's of grain got under the false bottom even though it appears to sit flat), and have some flow for a short time then stuck again. I got passed it using a straining bag, almost like a BIAB method honestly.
Anyhow, I've seen some use a hose cut down the middle to seal along the rim of the false bottom. Does this work well or should I just go with a braided hose, or maybe one of these bazooka screens?: