In other words, we go through Castles, for each Castle we go through 9 templates, and check how well it performs against Necropolis there. It needs to perform better on 5 templates than it does on Jebus Cross.
Specifically, Castle clearly performs better on SMAC, Balance, and Mini-Nostalgia, worse on Jebus Cross and Diamond, no idea on Skirmish, no idea on XL+U — it depends on player experience in such a matchup.