I tried this. I find that I can roll my wrists about 90 degrees from flat in the direction that a randonneur bear "flares" on the top.

But I then found that I could roll my wrists a full 180 degrees in the outward roll direction, which is opposite of how the randonneur bar flares on top, but which IS in agreement with the direction that any road or touring bar flares when riding in the drops!

So I will stick with my modified full-curve (Brampton bend) bars, and will flare the lowers only, just to the point of achieving any needed wrist clearance.
Seems like the best approach if one doesn't need any extra helping of rise, as from a taller stem or taller head tube.
The difference is whether the lower flare is created at the ramps (where my bending merely introduced some torsional twist in the ramps), or whether the flare is created in the top of the bar, where the bars begin curving upward closer the stem clamp.
The latter was popular as OEM on touring bikes, while the former was common on many standard road bends, so bending isn't usually going to be needed except with the fullest 180-degree bends and "squarest" top "corners".