I moved the home systems to account for map wrap. This design gives several different strategies to expand. Exploring to the end of your arm then out to the end of your wrapping neighbour takes time for little gain in the start, and planets should be hard to keep if the neighbour notices soon enough. Exploring into the sparse outer ring same thing with time vs gain to start but could be good bases for later raids into neighbours arms. Most of the action should take place in the inner ring and center.
Making a new post with a suggestion to deal with this issue anyway, and possibly make this round better for all players.