Hi Dean,
Managed code does not require Full Trust. Depends on which methods you use. In general, writing code is a bad practice in the client, since it leads to more maintenance down the road, but it does not require Full Trust deployment. Therefore, it does not require digital certificates. If you are writing a file to the local system, you will have to be Full Trust. In that case, you can just send them an MSI. That will require installing the MSI but that's easier than digital certificates (in my humble opinion).
Patrick Halstead
Project Manager at Qdabra