I've come to a handlebar/brake lever setup I love for mountain fix gears. Out of the saddle handholds that work all day. There is compromise on the flat and into the wind but in the mountains it rules. So much so that I'll pay the penalty 90% of the time to make the climbing time so much sweeter.
Wide pista bars with V-brake levers (and powerful Shimano dual pivot calipers). My old racing HBs were 39/40cm narrow. Now its 43 or 44 pista bars or criterium bars with the generously rounded shoulders. I push the brake levers halfway down the bar bend so they are roughly horizontal. (For me, the exact position as well as HB rotation is critical to keep my hands and wrists injury free. I do rides w/o bar tape and carrying all the wrenches until I like it.
Those V-brake levers made superb handholds, at least for these hands. Wide bars make better levers for rocking the bike so simply making the upper body work easier. And on that screaming descent on the other side, both of those features step up again. Wide = less aero. When you max speed is RPM limited, aero is NOT your friend!
And those levers? My first big descent with them was on my brand new TiCycles "Jessica". The bike of my avatar photo. I was a little nervous about tossing out all that power so I did a few hard slows and they seemed to work. From the drops, plenty of power. Got into the flow of the corners. Fun! Then I hit a blind corner steeper and tighter than anything I'd seen. "Oh ****!" Slammed on the brakes because I was going way to fast for my pedals to stay off the pavement! Pure adrenaline. And the bike slowed really fast with no skidding, no hops, just totally behaved. Went around the corner with 5 mph to spare. Blew me away. Best high speed slowdown ever on a braking combo that's supposed to be dangerous. Now, if you are a rider who rides the hoods that can be dangerous. It takes a lot more braking pull.
That avatar photo of Jessica was taken when my those pista bars and V-brake levers were earning their keep. That was a 2 mile hill with a patch at 14% and another at 14.5. Photo taken at one of those. (I never saw the photographer. I was a 60 yo in a 42-17 and my eyes were straight ahead. You can see the veins standing out on my forearms. When I touched them with bar of soap later it hurt.)
