Putting a group together?

I am considering putting 3 or 4 of my adult fat tails (1 is male) into a group in a large tank soon and I would appreciate info on what to watch for, what to expect, etc.

Questions:
What are signs of aggression, signs of breeding interest & signs of stress in fatties?
What behaviours are normal? What behaviours are bad?
Would it be expected that they will breed right after introduction, or is there a specific season for it?
Is there anything specific I should add/do/watch for?

The tank is 48x24x16, there will be multiple hides, moist hides, food/water dishes, etc.

Any and all tips are appreciated. Thank you.

Aggression (which is not as common with fatties) and bad behavior:
one or more geckos being scratched up, having bite marks, losing weight

Mating behavior: Male rattles tail and sometimes hisses. Males are usually quick to back off if female isn't interested

General behaviors: I keep my fatties in 1.2 groups and find that no matter how many hides I put out, they often crowd into one hide (not always the biggest one either).

Aliza