Ok! Here are some basic size comparison pics: Tantus Mark, VIP traditional, VIP Super Soft, and the Silicone Super 6
, which has the same listed diameter as Silky but is a half-inch shorter, and is probably much more stiff.
Reference shot of just me in underwear and longjohns (had I been thinking I would have put the harness on, it's not really designed for packing so it probably adds a silly amount of bulk.
I did try packing it with no harness but the base sort of peeled off me and was visible through the clothes.
Front view, side view, and sticking-out view in harness and longjohns:
Same setup, with a pair of Dickies over top (and the last shot with my hand where the head of the cock is:
My analysis---do it if you're gutsy, but you'll definitely have a bulge. I was glad to use a metal o-ring instead of a nitrile one because, as RVK mentions, it feels kind of fragile. If you're using a cloth harness system, you should be fine.