Since not all of the variables in the variables.less file are editable in the plug-in dashboard, you should make this compilation from variables.less.orig or variables.less an option. In my implementation, I changed some of the variables (e.g., navbar height) and it's helpful to just make the change directly in the variables.less file.
But now in the new version any modifications I make that aren't in the plug-in dashboard are lost. Until you make all variables something we can change in the dashboard, I think we should have the option to choose which file to update from. Otherwise, the only way to do it is now to change variables.less.orig which is not a good practice, since it would be handy to have the original around in case of apocalypse and since once we change it it's obviously no longer "original".
Thanks for the great plugin!