gRPC - Correct way to separate client and servers into different projects (.NET)

Question

We are transitioning a WCF based solution over to use gRPC.

We require both the Service and Client code generation that the Grpc.Tools package provides. However, we need the Clients to target .NET Standard 2.0 for comparability reasons.

Services need to call other services, so those projects need to be able to consume both the service stubs and the client stubs.

We also don't really want the service stubs to be exposed to consumers just wanting to use the gRPC clients.

This is proving a challenging requirement to satisfy.

Trial 1:

Have two projects, both importing the same proto files, each set to generate either the Server or Client.

Problem: A consuming project can't reference both server and client project due to the generated messages having duplicate namespaces.

The C# namespace is defined in the proto file itself.

Trial 2:

Separate the proto files out into messages and services. Have a models project which only generates the messages into code.

Have the client and service projects reference the models project, and import the services proto files to have them generate the stubs they need.

Problem: gRPC generates the stubs inside of a static class, which again has the same namespace in both projects so a consumer is unable to determine which version to use.

---

I now have two routes I can go down.

Option A:

In both the client and server projects, create classes which inherit from the gRPC generated ones so they can be exposed onto a different namespace.

For the services, this isn't so bad. The clients however have two constructors and a instance generation method which would need to be brought over to the child class.

Option B:

Create duplicate proto files for the service definitions, one having a namespace for the service stub and the other having the namespace for the client stub.

---

Both options have their downsides. Option A is probably the least bad as it doesn't require two files to be manually kept in sync.

Does anyone have any alternative recommendations?

Ideally there would be a way to alter the namespace defined in the proto files somehow when using Grpc.Tools, but reading the documentation, there doesn't seem to be a way to do that.