Mo, I tend to do the divirter on the back of braces low enough to catch and divert most of the water which might hit it, but high enough that any flow runs down high enough that capillary action will see it spread and then evaporate and not just be drawn into the mortise - 6" or so.

I've done the V and just a diagonal slash towards the shoulder side, thinking that likely to introduce less water into the depth of the mortise.

In considering weep holes it seems they would soon fill with sluff, dust and insect leavings, and water were it somehow directed towards them, would simply fail to flow and be held in that sponge.