he only objection I might have to "dub" is its old usage as an abbrev. for the two zeroes in the 24 hour clock; "Early shift starts at Oh Six Dub" (i.e., 0600 hrs) However, I don't hear this so very often, these days so I think it is a moribund usage.

"3 dub" has quite a snappy sound to it, but "dub-dub-dub" is too reminiscent of the open ceremony at the Wolf Cub pack to which I belonged, ah! so many years ago!