Hi,
I have experience for 15+ years in electronics/embedded development.
Also have a lot of experience in Microsoft .NET framework (C# mainly) and am used to develop communication protocols both in microcontrollers as well as in C# on windows.
For you particular project I propose developing a simple protocol where data is transmitted to the other end when changed. This protocol will have frame delimiters, as well as a frame checksum. Only the changed variable will be sent - a variable identifier is part of the frame, along with it's contents. Still haven't thought in error handling, but a simple ACK is my preferred method.
Some considerations may be need to be taken into account regarding simple priorities in case the same variable is changed "at the same time" in both ends - which one has priority, not to run into oscillations.
I propose doing a console application where the concept can then be easily integrated into another complex project by your own means/needs.
But these and other details can be further discussed in case I get the project awarded.
If you are interested in my bid, please feel free to contact me.
Best regards,
Carlos.