Here we can almost copy the Rust client tutorial one by one (https://0xmiden.github.io/miden-docs/imported/miden-tutorials/src/rust-client/custom_note_how_to.html).I think it is ok to create two clients in the browser.

The only question is, is this how people would use the WebClient? Wouldn't I want to use this custom note and send and receive the assets in my wallet?