I bought these ladder hangers from Home Depot today. I have used anchors before, but I tend to not make the right size hole. What is the ideal size hole for an anchor that takes a 1/2" thread? How much smaller should the hole be than the anchor?
Those hangars are designed to go into wood, but you should be able to install into concrete using lag shields, just as you would use with a lag bolt. My only concern is that lag bolts have a standards and ratings, where this ladder hangar might be of unknown strength, and could simply shear off in the lag shield. I wouldn't park my car next to or beneath it.
The lag shield has a specified hole size required, which should be documented, such as this one.