Sorry for the english, I hope someone can translate.
The way they get trunks like that in Taiwan is due to the high levels of humidity.
You want the tree to produce aerial roots on the branches, but close to the trunk. This way you can then tie them onto the trunk and feed heavily to get the roots to thicken and fuse.
Once fused, you have to slow down with feeding. If you continue the heavy feed the trunk will start to smooth out loosing all the work done. But you can stop feeding, as those roots that are now fused are no longer supplying the crown.
They don't worry about nodes much, as they work on a stock tree with short nodes and then fuse the short nodes on.
Remember Ficus HATE the cold... keep them warm...