How did these grommets/plugs work out for you? I am shopping around and still wondering whether 1/2" or 5/8" is better. Also found these.
Amazon.com: Rubber Hole Plug for 5/8" Opening - 3 Pack Grommet Without Hole: Home Improvement
Haven't bought it but will now and let y'all know. I'm getting mine rustproofed with POR15 then Fluid film the week of October 21st. I'll ask them to take some nice pics before they take it down from the hoist.