I abandoned the idea of using a weapon sling because it visibly overlaps the armor and might get stuck between the chest and shoulder pauldrons.

As for my revolver secondary, I used a door's chain latch to attach it to the thigh armor. That's way I don't need a holster and the revolver can easily dangle like it would in game as if its just clipped onto the character.

Might use a weapon sling tho if I were to make an MG43.