I hope the information contained here will be helpful and accelerate the grow of your colony.
At the same time, tinkering with paths, gates and machines is the core of the game so please consider this guide as a game mechanic spoiler. But if you are tired of reinventing the wheel or just curious…
enjoy!

If you find a bug, an area to improve or a typo, please let me know. I’m happy to develop this guide further.

While I've been racking my brain about designing energy colliders for the first time I made an interesting observation. When colliders face opposite directions they create huge empty space under the coil.
I thought this space is occupied by building, but no… it is completely free to use.
That was a breakthrough that allowed me to create 100% space-efficient design.

The setup I will describe is designed to have one sustaining collider creating energy a tier VI energy pod from the basic one – tier I. However you can adjust it for your needs. For example if you have access to a green energy pod from the Jungle Island you can cut 16 machines and start with creating an e.p. tier III.

Energy colliders recipes:

Space: you will need at least 8x10 tiles.

Costs:

• Energy colliders x 31 = 310 iron, 310 glass, 62 iron plate, 93 diode
  
• Slinger x 31 = 155 iron, 620 screw
  
• Smart dispenser x 31 = 310 copper, 31 LED (can be replaced with free dispenser)

Technology:

• old gate (could be updated with life gate to squeeze more from ant lifespan )
  
• stockpile gate/timer gate – to create nested counter lines (timer set to 99999 minutes, stockpile gate not connected to any stockpile)
  
• slinger
  
• null trail
  
• and of course energy collider ;)

First we need build 8 machines in a row and create simple 2x2 square hauling trail directly in front of them. If you leave no space between machines there should be nice 4 ticks between squares.
Squares need to go clockwise! (it could go counter clockwise but then you need to mirror a lot of elements).

Now we create null trail supplying machines with workers. It is need to be right next to square.
From the line we draw counter gate - simply one worker to one machine.
Counter should enter square on the left side.
The line should lead from you main ant trail and start with counter set to 8 (or your number of machines in line).

Next power step is simple but work magic. Nested counter.
Sound complicated but it is one additional gate really.
It could be stockpile gate connected to nothing or timer gate set to 99999 minutes or even caste gate set to ant that you never expect to enter system. Stockpile gate seems to be the best as they use no compute power – no checking caste or counting time.
The trick is to lead this gate from the square back to supplying line (as marked with yellow arrow)
After you set it and highlight counter gate on the beginning all squares should be green as counted in the system. Simply magic 😊

Draw elder trail along supply trail. Add elder gate or life gate (for better efficiency) leaving square from the right side.
Remember always when ant die without being repurposed or recycled somewhere puppies died (hopefully also without being repurposed or recycled).

Add dispenser/smart dispenser on the left:
and slinger on the right:
After entering the loop, ant will take an energy pod, put it into collider then either go to do second round or wait till fuse happen, then continue with higher tier energy pod to the slinger. Either way in moment of going through elder gate/life gate ant will be empty handed.

Remember to choose recipe in the machine, connect dispenser to the right stockpile or choose material in the smart dispenser and create a stockpile to collect fused energy pod. Like this:
It is a good idea to add overflow path for the case if you accidentally set more ant in the first counter gate then you have in line (in tight spaces between colliders ant could die unnoticed and remember, always when ant die… ;) )

And now the best part.
Becouse colliders have this huge empty space under the coil you can put next row extremely closely:
From now on it is just build and repeat, except last fourth row where you need only 7 machines so you can make space for the stockpiles as on screenshot:

System is flexible, you can make row of machines longer or shorter, delete two rows after you start collecting green pods from jungle pod or three row after… hmm that would be a spoiler 😉

I hope this guide will help you build a compact collider setup.
Your comment would be a greatest complement for me.
Thank you for your time! 😊