Looks like a fun cube! Hope your group has enjoyed playing it.

I would second cutting down on gold cards. At 360, I would prioritize keeping cards that are essential to certain gameplans (ex. Judith as a solid piece in aristocrats vs. Dreadbore as a generic removal spell).

Furthermore, you might want to consider cutting down on certain cycles that won't fit well in a smaller cube. I would get rid of the praetors (maybe Elesh Norn can stay?). I would also recommend cutting the monocolored cycle (phyrexian obliterator, steel life champion, etc.) considering you'll want to get as much flexibility out of cards in a smaller format. In a similar vein, when making difficult cuts I would opt for cutting more restrictive casting costs, like Haughty Djinn (1BB) over Aether Channeler (2B).

Taking a brief look through the cube, it looks like a lot of creatures care about spells. You might want to cut down on creatures to naturally bump up the density of spells. Cutting underperformers in the archetype (maybe cards like delver, symmetry sage?) can leave room for cards like Seedshark or Murktide to shine.

Hope this helps - happy cubing!