Is it OK to install my vynil window by inserting screws at the top and bottom instead of using the the two pre-drilled screw holes at the sides? I am replacing an old basement window with a new "hopper" window with a column of glass blocks on both sides. My original plan was to anchor the window to 1" X 4" lumber between the window frame and the glass blocks. After I got my window, I realized that window frame and the slim-line glass blocks are the same thickness and that I would have a more aesthetic look if I could eliminate the 1" X 4" and apply the glass block cement directly to the sides of the window frame. Would I be making any structural compromise by doing so?