I'm using some very good $15. Bar-Ends I got on Ebay in conjunction with some repro Hella Bar End Signals. The mirrors are slightly convex & steady enough to give an excellent view.
I have found good mirrors to be very valuable in spotting car top Light-Bars before any mischief is done. Enclosing a picture of mine. Cheers!
I use the same mirrors (only in black) and I love them so much ~ I bought a second set just-in-case I crunch one.
They are cheap, work well, and slightly convex. - the perfect combination !
I'm not worried about light bars sneaking up behind me, I ride mostly on the belt-way 'round town and I'm watching to make sure I don't get run over !!!!!
I like your signals! where did you get them? Do they make them with an acorn shaped lense ? how is the wiring routed ?