Should I use staples or attachment for 6/2 cable?

I am installing 6/2 Romex cable. I have previously installed 10/2 cable, and have installed larger cable for a subpanel feed. For my 10/2 wire, I still use staples, although it is those strap versions designed for bigger cable. For subpanel feeds, I use single hole metal straps, the same as the existing panel feed.

I can't seem to find a staple rated higher than #10 wire. I guess I could put it under single hole straps, but it would fit loosely, those are not really designed for cable.

Whats the correct answer here?