SBC for a dense cluster, options?

[boulder47]

Hi,
I'm thinking of creating a small cluster of sbc's (pi or other) in like the 10" rack space, (like the DeskPi RackMate rack)
My question/thoughts are how many nodes of which type of sbc could one densly pack into a rack.

Have you had any experience with the Radxa Zero 3E, with the Ethernet rj45 built in,
Something like that type of sbc might be beneficial in a dense space.

At what point is it better to use a pi cm5 based cluster if the carrier board isn't too big?

Cheers.
Boulder