I find it difficult to believe that this could actually be done. Or rather, that the amount of effort would ever justify it. You'd have to account for surface-to-volume ratio, glass thickness, radius of the corners, etc… And that would just be for a cylinder. No two bottles are the same shape.
I don't think there's any problem with counter-pressure filling a standard longneck to any practical pressure. They're rated to 3-4 atm and at cellar temperatures that will do >4 vol CO2. It's when you need to carbonate at room temperature that you might have issues. Even then, 45 psig is ~3.5 vol, though as you said you'd probably want to retain some safety margin.