This is true, Feyszar. You'll need to half the object spacing if you half the size of your object, and double if you make it twice as big.
Proper scaling of objects needs to be done before they are tgo'd, in another app'. I use Carrara and Poseray to scale/texture models respectively. Otherwise, you'll need to rely on TG2's 'scale' boxes, I've seen myself using scales of 0.05 for some shared models, everyone wants to make them massive.