I lied, I couldn't get this simulation out of my head so I had to code it up.

Very interesting results. Initial simulation gives me 6 EPA over many runs if you include the chained volume card, 5.5 without it, which seems high but has been going down as I find and fix bugs. Will keep going - there's a lot of cards and random edge cases. This is about what is listed as "average run" and below what's listed as "multiple optimal runs", and takes into account the actual frequency of being able to draw the chained volume.

(Caveat - I coded it up with my stats, which are endgame stats and I've got lots of items but I don't 100% some of the checks. In addition, code up the sim I had to pick a priority order and strategy for when to play what cards - I make no promises about how optimal that strategy is that I picked. I have not optimized this strategy yet)

(Other caveat - I have not updated this simulation with the latest update. I suspect the overall conclusion is the same - if there's a way to convert stuivers to echoes then this is the most profitable grind out there because of the existence of the chained octavo, if not then it's the best stuiver grind but has no use outside that.)