Q: Use of higher-wattage PSUs

I have an impressive collection of old Magsafe power units in 85w and 60w configurations in addition to the 45w adaptors for my MacBook Air 11in. I like to leave PSUs around the house, at work and at other locations so I don't have to keep unplugging and carrying around and I would like to be able to safely employ these old adaptors.

Are there any contra-indications to the use of higher-wattage units with the Air? I note that the Magsafe supply from the Cinema Display copes with any MacBook, irrespective of the recommended wattage, so I am wondering if all the supply units are self-regulating in this way.