It can be difficult to distringuish between “0” and “O” in the callsigns and it would help get the callsign correct first time if the in game font used either slash or dot zeros for readability. There are free (even for commercial use) fonts available that provide this such as https://www.brailleinstitute.org/freefont/#download for example. There is also a Microsoft monospaced font with a slash zero that Notepad uses by default (Consolas).