I would like the triangle-shaped extension as another hand position- both hands like 45* from full pronation- but I think that the extension would really need to be angle-adjustable so you can keep your wrists otherwise straight, just as you want your wrists straight when they're on the hoods.

I actually did once see someone riding with his hands like that, I don't know if he had that bar or a clamp-on extension for a different set of bars.

OP, is the reach and drop to your liking?