Talked with Ultimachine about the discoloration and 'bleed' present on several screens.
Ultimachine responded earlier to me after they had reached out to their supplier and responded with some corrective action they will be taking on their part. This also includes some corrective action for the 'bowing' of the screen.
For the first picture, It is obvious that the contrast set to too thick, Pls change it to darker and try again, It will look much better that way, They looks a little bit bleedy because STN type display have limited viewing angles, The color will looks different when viewing from different directions, Yet the color will also change due to slight voltage difference on each pixel.
For the second picture, If you adjusted the contrast to darker, The bow shall disappear or at least not that prominent, You will see bow problem because when metal bezel gives pressure to the glass, The structure of the glass cell will change which causing such a effect, This kind of problem normally exist on Yellow-Green or White on Blue display, If you could use Black on White type, There won't be such a problem.
Ultimachine has sent us a min and max samples of their range that they will be setting the voltage on V0 at for the screen. One of them also has an extra hole on the back where we could adjust that pot after the lcd has been assembled.