how the caching rules apply when opted weight based traffic manger between Azure and AWS endpoints

I have a traffic manager in Azure and which has 2 endpoints(one is from Azure and another is from AWS), and each endpoint has similar caching rules. I have a couple of questions here

1. If a client is being served the resources from Azure and what are the chances the same client will get resources from AWS? In this case, how the caching rules for the endpoint will get switched from Azure to AWS or vice-versa?

2. If I want a few clients should receive traffic from a particular endpoint, how can I achieve this with Weight based traffic management?