Question: how to change machine type of an existing JupyterHub on K8s


I am currently running a JupyterHub on K8s following the amazing Z2JH documentation. The cluster is set up with a default-pool and a user-pool. Both are n1-standard-2 machine types. Given a class around 80+ students, I have to downgrade per-user RAM guarantee to 64M to accommodate all students to login during lecture.
I’ve tried resizing cluster to increase the max number of nodes on user-pool, but I hit the GCP quota limit(I am still requesting more quota limit through local sales team at the same time.) So I am wondering if migrating the user-pool to n1-highmem-4 is an alternative?
Is there any resource recommended to study regarding the “change of machine type” of an existing JupyterHub on K8s? I’ve tried but did not succeed.