[Sephiroth]

Your plan is sound. The main thing is to give the SH the minimum amount to do by turning off wireless & firewall. This leaves it mereley to route out to its four switch ports.

You'll want to allow for double natting if your devices are sensistive to this; you'll need to set each router into bridge mode with own discrete DHCP range for serving out to their attached devices. Double natting takes care of addressing from the SH to the appropriate router.

There is no reason I can think of why the solution you propose shouldn't work with stability.