That's a pretty nifty world map!
Alright, I'll make sure the model scaling function is put in there. I am thinking it will be a function that can be used after importing the model, something like "Scale By Geometry" which shows a dialog where a scaling factor can be entered and hitting "Apply" will automatically scale the layer according to its internal vertex positions and the entered scaling factor. Then you can just hit "Fit Canvas to Layers" on your canvas properties to have the canvas volume's dimensions automatically envelop the model afterward - or perhaps add a checkbox on the scale by geometry dialog to just automatically scale the canvas all in one go. I'll have to play around with it a little bit to see what feels right.
I have a handful of other features/functions to add before the next update, along with recording some more capture for videos, but the update shouldn't take more than a few weeks :)