Since this node drops Ceremonial Sword of Twilight, I’m going to farm the shit out of it, all while bonding with Vlad & Bazett for future lv120 goals (and extra quartzs for Tiamat coming next month)
If you only care about clearing the shop optimally, the cheapest 5 slot comp is Iyo-RulerDaVinci-Castoria-Oberon: you don’t even need Black Grail, just a maxed Ocean Flier will give Iyo enough damage (and you don’t need lored append).
The cheapest 6 slot is probably Gong-DaVinci-Castoria x2-Oberon, but remember that it’s fine to 3 turn this node, so other options without the extra party slot are on the table.
There are a lot of other comps available, since almost every Ruler in our Chaldea has special damage against Ganesha (to top it all off she can also bully herself with her own powermod LOL): in particular ruler Skadi works as both primary DPS and meta support for this node.