Greetings! The answer to your question “What impact on Wyse 3040 CPU and memory usage does BCR it have? I am asking as I have the chance to buy Wyse 5070 ThinOS clients and was wondering if the more powerful client would give users any better experience if it comes about BC”, is yes. The 3040 is designed for task users not using multiple published applications or desktops. The 5070 will provide a better user experience, specifically the version with Pentium.
There is a Dell document that discusses how to configure Citrix Browser Content Redirection policies for Wyse ThinOS 9.
Hopefully, this helps you with your questions.