Dense cables can only support 32 channels. Smart cables and regular cables can only support 8 channels. One face of an me controller only supplies 32 channels. You can combine me controllers together to form a multiblock structure, just keep the controllers in a 7x7x7 area. The me controllers can not be combined to form a solid block as in you could not put 8 controllers in a 2x2x2 area. I usually just do a single line of controllers for simplicity. The rules are something like an me controller can only be connected to two other me controllers. You also can not have two or more separate me controllers on the same network. The me controllers have to be connected to each other. The me interfaces, level emitter, and import bus each require one channel so you would need 45 channels. If you hover your cursor over an me dense cable or smart cable, waila will tell you how many channels are going through that cable. There are more efficient ways to make channels available throughout your base using p2p me tunnels so that you could run 512 channels through one dense cable with just 4 me controller blocks, but that gets a bit more involved so I'm not going to get in to that unless you really really want me to. I'm not the greatest at explaining things so it might be hard to follow.
A basic setup for your 15 ballad of alchemys would be to run two separate dense cable lines with each one connected to a different face of an me controller. One dense cable line would be run near 7 of your ballad of alchemys and the other dense cable line would be run near the other 8. Then for each separate ballad of alchemy, connect smart cables or regular me cables to the interface, level emitter, import bus and dense cable. Keep in mind that it can sometimes take a little bit before the connections become active. Connecting things to an me system are not usually instantaneous. This also applies to the waila tooltips. The tooltip has to wait for the me system to update. Also, the tooltip for the cables only shows how many channels are going through that particular cable. If you want to know the total number of channels being used from one me controller face, you would have to look at the cable connected to that face or any cable before other cables branch off. I hope that makes sense.
Edit: Now that I submitted this, looks like you edited your post and got p2p tunnels working. Nice work.
Also glad i don't need to explain p2p tunnels.