As far as anti roll goes, the flat portions on the head provide very little stay. It's fine for surfaces that are designed to be flat but maybe aren't perfect. If it's the truck deck of an automobile forget it, it's going to roll.
Regarding the lanyard attachment, JB makes a stainless, slightly crenelated tail cap with a hole in it.
Scroll to the bottom of this page:
http://blackforce.stores.yahoo.net/raptorrrt1.html
It also allows tail standing
With regards to the lanyard ring from Lighthound, there's no issue with the installation as it fits between the cap and body at the natural space that's left there. If you look at my picture I've got a green colored o-ring there. It has nothing to do with the o-rings that seal the tail cap since those press outward from the body against the inner wall of the tail cap. There's no water tightness compromise. Think, "flat washer."