Hi, with regard to the 'space allowance', I had a problem like that in 'Classic' FP, when I needed to 'interval' a bunch of objects without worrying about 'snap to grid' and clearances.
IIRC, I was importing them anyway, so I used TurboCAD to add a 'zero-thickness' rectangular plinth, which 'squared up' their extents and 'footprint'. With 'collision detection' enabled, I was able to insert and place them like kiddy 'Duplo' bricks or decorative tiles...
Um, does TFP have a genuine 'invisible' texture ? It was long on FP's wish-list...