Installed the gas strut on front door this weekend. Works well and I am pleased.
What no one mentioned about the installation I read, is that the 2 ball attachments must be at least 1/2' to 1" wider than the length of the gas strut in a fully closed position.
In my case, with the 20" inch / 15 lb strut, that would be about 12"
I now have a couple extra holes that need to be filled.