Has anyone used 3/16" shock cord? Is it acceptable?

Will paracord 550 work for perimeter safety lines?

3/16 shock cord (vs 1/4 ?) is what I always use; it's also what Mariner put on their boats. For my boats, shock cord is only for 'securing' gear, not for grabbing.

The 550 paracord I've found is more like 1/8 when it is well stretched - and it will stretch a lot. It's also a bit 'soft'. I prefer polyester yacht braid for deck lines.
It's also nice to have something thicker to grab (and visible to see) when you are in the water and want to grab the boat quickly. 1/4" black (or white) deck lines will look more friendly then! ;-)
(I have used 3/16 deck lines on some boats.)