The movement of the yoke corresponds to the movement of the ailerons (and elevators of course) and the full deflection of the yoke (in this case 90 degrees) corresponds to full aileron deflection . If you restrict the yoke movement by 50% (from 90% to 45%), you are restricting the movement of the ailerons. You could do this, by using a Lua plugin (by checking the aileron deflection value and limiting it to a maximum/minimum) , but it is not recommend as you would be losing the ability to move the ailerons through their full range.
If you want full aileron deflection but only to limit the visuals of the yoke, then this is almost certainly not possible as this would have been implemented by the aircraft designers and based upon the yoke movement of that particular aircraft.
Hope this helps. Regards,
John