Gas Tank | Shape of Bottom of Tank

[BTR]

2005 RXT 4-TEC 215hp.

Does anyone know what the shape of the bottom of the fuel tank is? Is it FLAT? Is it CONCAVE? Is there a DEPRESSION where the fuel pump sits in it?

I plan to vacuum out the gasoline in the tank (using a pump certified for gasoline). Therefore, I need to know if it has a "low spot" at which I should place the vacuum hose? My objective is to remove as much gas as possible.

Thanks for your help!