Camera alignment to workspace issues

I have S9 with Y axis expansion. Overhead I have securely fixed a 5MP light burn camera 120 degree viewing angle. The camera is physically aligned to the centre of the frame in a way that it can not move. I use sculpfun honeycomb which measures 400x800. The honeycomb position is fixed relative to the frame using a jig. The camera is aligned in portrait mode.

I have repeatedly calibrated the camera and alignment.

I can never get the whole workspace centred in the overlay view. There always appears to be an offset in the X direction. I can change it a bit in X by changing the machine X size in machine settings.

What is the best approach to this? Set X and Y to the physical size of the frame or actual workspace size by jogging to the extreme X and Y and reading the head position.

Many thanks in advance for advice.

Ps in the calibration when the software shows a raw image from the camera all 4 corners of the frame are in the FOV. I have limit switches installed

I have it working now. This Is what I did.

(1). Physically aligned bottom left corner of honeycomb to 0,0
(2). Measured exact X dimension (390mm). smaller because of the air assist nozzle takes some space
(3). Measured exact Y dimension (800)mm. Both case by careful jogging
(4). set dimensions in settings to 390 x 800
(5). double checked 390,800 goes to correct position
(6). reran camera alignment
(7). checked using position laser tool and test piece