Always Automatically 'Right-Size' All Finder Window Columns Individually? Is there a way to make all Finder Column Views automatically 'right-size' all of their columns individually by default in OS X 10.10.x 'Yosemite?'
The only solution up to OS X 10.10 (Yosemite), is to download XtraFinder - a free app that is very useful for your issue as well as many other things, including restoring full coloured labels rather than OS X's silly little dots. 
Sadly the full functionality of XtraFinder was destroyed initially when El Capitan came along but if you don't mind disabling System Integrity Protection some of XtraFinder's features can be restored. The guy who publishes this is working on an update that will restore everything in El Capitan, later. You can plumb the internet to get more information about XtraFinder and also how to disable SIP.