Similar, but not the same at all really
, on my 1000SS project I ended up using two tiny rear Rectangular rear lights as I felt one was too little:
They are sold as Road legal, are Very bright, show a big difference when the brake light is active, and my MOT guy confirmed a few months ago that he was happy with them.
Although the bike is booked in with him next week when I'll find out for sure.
Nasher.