Was wondering what your set-up on the bottom looks like in regards to collecting xp and items.
That server was a while back, so I probably don't have it anymore to take more screenshots.
From memory, the floor is solid reinforced obsidian. The Transfer Node (from extra utilities mod) can be placed up against the bottom middle and upgraded with World Interaction Upgrades to allow it to pick up items in the world. With two upgrades inside it has a reach far enough to grab the items out of the spawner without line of sight. I did not collect the exp orbs, as I had 100m+ Mb of liquid exp from my other (less explosive) spawners collected through a vacuum hopper, so I have not thought out an exp orb collection functionality.
When I get home from work i'll check if I have the old map files on my public server and fire it up.
*The transfer nodes are also the fastest cobblestone generators for making bedrockium drums, you can easily make tens of thousands of compressed cobble very cheaply (provided you can store it!)