I would think if you would like to stabilize the swings in your tank a bit, put a ATO on it. It will stabilize your salinity at the very least. We all have evap but with a nano you see it so much faster. As long as your levels are stable, the only swing you should really be having is with the salinity so I really do think that having a ATO would sincerely help you out.
I personally find my 60 gal easy to maintain, a 100+ is great...if you have the room for it and if you have the time to maintain it. Water changes on a bigger tank can be a ***** to do and unless you own your own home youll eventually have to move it. Add to that the extra power costs of it.....you just have to be ready to "go big or go home" and there is more to it then just not having to worry about swings in your tank