60 degrees isnt hot, 75 is hot, 60 is downright cool in some parts of the country.
Below 75 or so I take a 30 degree bag, its all that I find I need. In warm weather I sleep on just the pad in tent well ventillated, use the unzipped bag as quilt, pull a little bag over my midsection leaving feet and upper body exposed when I first go to sleep. Usually I will wake up much cooler several hrs later and cover with a bit more bag. Can shift the down to one side, top half for instance, and basically have option just cover with the bottom half without much down if want too. very flexible bag with continuous baffles.
Others use a bag liner , simple sheet. When it gets really hot and humid and sticky, use nothing at all, but still bring the bag cause you never know, and it makes a good pillow.