As you sort of stated in the OP, bullhorns are road bars so will be 26.0 with a few exceptions i.e. some ones Nitto make which are available in 25.4, but they are flat and look like chopped & flopped drops.
@MaxC started
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As you sort of stated in the OP, bullhorns are road bars so will be 26.0 with a few exceptions i.e. some ones Nitto make which are available in 25.4, but they are flat and look like chopped & flopped drops.