I think the Geomancy set should be updated :
- defense EVs are better than HP EVs with all of its counters being physical (priority or not), Geomancy boosting SpD and its HP base stat being so high : this make even CB Scizor always failing to OHKO after SR damage
- Psyshock>Thunderbolt in my opinion as neutral Moonblast>SE Thunderbolt (Lugia and co) and not very effective Moonblast>neutral Thunderbolt (for example on Aegislash), while +2 Psyshock does also more than 50% on most Ho-oh and is your best option against Blissey, Arceus-poison and in some CM situations
- about your comment : Geomancy Xerneas should be used as a late-game sweeper, so the fact you can use it only once isn't really a problem if you use it this way
Any relevant calcs that the Def investment allows it to avoid? The extra SpDef that HP investment provides is useful to allow it to set up. I did put Psyshock as the first option but Thunderbolt does hit Ho-oh a bit harder. I stand by what I said about it only being able to set up once. You are playing with 5 Pokémon until you manage to remove all their Xerneas counters, some of which are very bulky and difficult to take out, unlike Arceus-Ground or CM Ogre for example, who can set up repeatedly over the course of a match.