Both options would use the same number of CPUs and director boards.  So really no difference from that perspective.  Using 4 enclosures would separate the cables further from one another, which can improve availability from "fat fingers"
I am working on port groups for vmax 20k and would like to know the best practice with pros and cons with selecting from 2 engines are 4 engines.  What would be best practice amond these  Group1: 5G:0, 7G:0, 10G:0, 12G:0 spread across 4 engines.  Group2: 5G:0, 6G:0, 10G:0, 12G:0 spread across 2 engiens?   Does both directors share cpus with engine or do each director has dedicated cpu?
Port Group Selection in Vmax 20K