The adjacency bonus is calculated for every side of every technology, and added to total, before the tool/ship's class bonus is calculated. It is calculated by multiplying:

• The hidden "bonus power" stat of the technology in possession of the side

• The hidden "bonus multiplier" stat of the technology the side is facing towards.

What this basically means is that you should place as many of the same family next to each other in a box shape, making sure your best one in the family has the most others touching it. Some may benefit from a + shape, but it's not worth the disruption to your layout.

The videos at the bottom of this page may help to explain this concept further.

My layout for ships no longer includes trails & bobbleheads, as you simply cannot fit them in as well as the other stuff. Feel free to pick a weapon or 2 to not feature in your layout & use those slots for the trails & bobbleheads (or just use 2 slots - 1 trail, 1 bobblehead).