TBH, For the most part, I avoid giving someone an exact mm measure because the concepts behind how a number is arrived at are more important. Besides, imagine some people just getting a number and then telling their surgeon they exactly need 'X' mm and 'because someone told them so on the internet'.
What I look at are ANGLES which are not actually mm measures. However, mm measures as to advancements are FUNCTIONS of what the angles are and how they are to be changed via the surgery.
what I can tell you, is what you probably know already which is that you are LOW ANGLE for both OP and MPA. On CLOSER INSPECTION, your maxillary plane; (ANS-PNS) is oriented in the CCW direction. So, that combo veers in the direction of getting a CLOCKWISE rotation. For example, the max. plane angle is approx 6 deg in CCW direction. The OP is approx 0 deg and MPA approx 14 deg. A CW rotation to bring your maxillary plane closer to 0 (meaning closer to the horizontal plane) would bring the OP closer to the norm and yOUR MPA closer to the norm. So, with a CW rotation of maxillary plane, linear advancement from THERE would be preferable to linear advancement (in your case) over your present maxillary plane angle.
With that, will come some 'straightening' of the nose to lip conCAVITY which will go towards getting closer to norm for nose to lip angle. So, there is some 'room' to advance maxilla along very close to a horizontal plane if it's present CCW orientation is counter rotated to be closer to the horizont. Do that and the bimax advancement could be linear to GOOD effect UNTIL it reaches a mm amount where the nose to lip angle goes beyond 90 deg.
Now, under those circumstances that would be favorable to your aesthetics, what the near equal bimax linear advancement would be (after the maxillary plane was de rotated to be closer to 0 inclination with horizontal plane) will depend on how much they need to open the airway/s.
I've read that an adequate posterior airway diameter is about 12mm. Your airway on the ceph doesn't look like a narrow straw. But your airway diameter would need to be a KNOWN in order to know how many mms to increase it which, in turn would directly relate to how many mms the maxilla would need to be advanced. IF Not 'that much', THEN an overall aesthetic improvement could be had. IF 'a lot', then with that can come trade off conVEX nose to lip contour.
That said 'How far can you move your jaws...' (and get an aesthetic improvement from it) in terms of an 'exact' mm amount will depend on an UNKNOWN (to anyone on here) which is your present airway diameter.