Installed the acrylic. Sanded the outside 1" perimeter of the acrylic to give the glue something to hang on and cleaned it with rubbing alcohol before applying the glue. Used 4 tubes of marine 3m 5200. The liner made it a little thicker then we expected to get the window in place but its in. We are only pushing around the edges of the tank where it is pressing against the wooden and aluminum supports. We used clamps at the top of the window, Car jack and wood in the middle of the window and wedged some 2x4's at the bottom. The liner will be cut where it is over hanging outside of the tank later.
Is the liner glued in the tank? The only reason I ask is you have the liner going under the acrylic. If it's not what's holding the acrylic to the tank if it's glued to the liner. You could of used the liner as gasket and bolted the sheet to the frame