Argh^^ I dont get it^^ The reflection capture actor does exactly all that for you with the console command I just mentioned 
Its a local cubemap capture that applies what it captures to the scene around it based on the radius you set. It captures diffuse and reflection. Exactly like like what you described but without that bad workflow^^ There is no difference in capturing the scene with a reflection capture actor vs. scene cube capture if you use the command, only the workflow is better.
So either I really dont understand you, or you dont understand me Sorry^^