There is a commercial tool, https://www.ccboot.com/, that exists for your use case (gaming center with netbooted clients), and iirc they provide an option for saving CoW to a local disc.
Not the right thing for me personally, since it looks like an end-to-end solution that replaces a lot of stuff I've already figured out and customized to my liking.
Would be interesting to know how they did that local CoW... did they write a custom Windows block device driver?