Yes. I am following the Scheme tradition of representing immediate values as tagged pointers. And (ref i31) is the obvious choice when using WebAssembly. I am happy you and the team added GC to WebAssembly.

Details on the representation.

https://github.com/soegaard/webracket/blob/main/compiler.rkt...

I am more or less only using the linear memory for the JavaScript FFI. FASL-encoded values are passed back and forth to JavaScript.