On a related note, where can I find stands that are made from frame rails? I have stands with a U-shaped top which I use with a piece of plywood to spread the load on the rail.
Mine do as well - doesn't seem to be an issue.
DAYTONA 6 Ton Heavy Duty Ratcheting Jack Stands
And yes, I know Harbor Freight has sold bad jack stands in the past. The above ones seem solid though.