CUSTOMLED rocks! Bar none!
as for the Watsens being "too small and directional"... lol! Sorry, that just cracked me up. I don't think you really looked at them. Those suckers are 120 lumens, 4 watts! If you need a better idea of how bright and unidirectional they are, check out the pictures in this thread: https://www.wristtwisters.com/forums/...tml#post525877
Look at the black 919 with the rider wearing a blue helmet. You'll see that even though the Watsens are taped over with heavy duty painters tape, they STILL shine through the tape, on a bright day in direct sunlight! Even more, that's just the running light output! Turn signal output is much brighter.
The Watsens are no joke, they're the best of the best. Sadly, I can't recommend them for use as front signals ATM since they don't offer the running light option anymore (which I require). You could fab something yourself if you so desired in order to add the running light functionality. If you're looking into intergrating the rear with the brake light, the CUSTOMLED integrated unit is the way to go. If you want to retain the stock brake light, then I highly suggest you get some Watsens and fab up a mount at the grab bar holes like you were thinking. Ideajones fabbed some up and I'm sure you could easily adapt the Watsens to them. They're small and sleek, but you just cannot beat their light output!
I don't think anyone on the forum has used the CUSTOMLED flushmount indicators, or at least they haven't posted their experience about them yet. Seeing their quality on the integrated unit, I wouldn't be surprised if their flushmounts have awesome light output. However, I don't think a clear lens such as what you posted above (which the CUSTOMLED requires to be retrofit into) would look good where the grab rail caps would be.
edit: Damn, looking at those pictures just make me lust for another day at the track!!!