Remember the guy with his helmet glued to the beam?

Just a thought.... I would consider putting one set of angles in place, attach them to the sides of the tank, then adhere the baffle in place, then put another set of angles which would sandwich it together. That's if the tank is stiff enough.

If the tank walls are moving around under way, or the tank isn't locked in, etc. ... Then you might allow for movement by using a set of slotted connections.