With plenty of fixtures able to push a single shutter all the way across the beam it would be very useful to be able to visulise this accurately
Are you referring to conventionals or moving lights?
Movign lights, it came up trying to program an effect on ViperXIPs but seems consitant across all full curtain shutter fixtures I tried.
If you can send capture the dmx levels at which the shutters touch when you insert the opposite ones into the beam, that would help to correct the fixture profile. It is not always accurately in the manual, so user reports matter.