I just discovered this and although it’s a few years too late and I’ve spent ages messing about with placeable heights it’s better late than never so if anybody didn’t know this then I hope this helps…
I always select placeables to go on tables etc. and use the alt and mouse to get them at the right height or the mouse wheel and sometimes it takes ages and you can’t quite get it right, I’ve even resorted to changing the position figures in some cases, but…
Stick everything you want to go on top of something else on the floor select them all and in the properties select stackable then move them straight over to the base object and they all jump on it at the right height !
It’s so simple, I discovered it by accident when I selected the stackable box by mistake and a bottle jumped on a table as I moved it.
Stacking will never be the same again but will I now have to go through everything and move all those bottles with no base or floating candles ?