I used a couple of time the neat mechanic of the Chamber. the chamber is actually 3 tile tall, and if you pass stuff trough the tiles above and below the side entrace, they will actually align in the chamber. it work also in diagonal so yeah- for those who still play this, here my most compact design so far, along with some explainations!
(it make Ultimium btw.)
Edit: Oh you can see on the bottom left chamber, an electron getting aligned like what i said earlier!
i didnt noticed until i checked the pics. this technique also helps not have weird bumps in your loop
PS. you see the brakes beside the Electron spawners, theyre just my switch off, i move the spawner on them when i needed to work on a section