I have clip-on aero bars on my townie/tourer. A big plus to take pressure off my hands, but needs improvement to use for long periods:
- The forearm rests are not far enough apart for comfort. I bought used a later version with flip-down rests which space wider, but it clamps on just a bit more outboard, so may be into the taper transiton part from 25.4mm to 22mm, I'll need to test. I need a wider middle section. And...
- For comfort, I need to raise the aeros about 70-75mm, without raising the flat bar. For my current aeros, easy, because the bars are anchored to the top half. On the later aeros, they come from the bottom half, so spacing up the forearms alone would make a funny angle to the bar front and also tilt the pads the same way. And, Profile says the spacer is incompatible with either bars, when it looks totally compatible. I think I know why: The spacer is laterally narrow, so the wide forearm pads would impart a bending moment on the main bolts. (This would not be an issue if the forearm wings were a one-piece span.) So my current thinking is to find a flat bar with a wider middle section (if need), and space the aeros up using a "double-clamp/stem", however the aeros attach very close on each side of my current stem, where the double clamps would normally attach, so they would need to be further outboard on the tapers or 22mm dia. So I'd need to make that work. And, so far I have not been able to find double-clamps near 75mm center-to-center, only about 40mm, so there's that. If I can solve all of the above, then, between the flat bar, bar-ends, and higher aeros, I would be dialed in for touring hand positions.

I also put an interrupter/mid-cable front brake lever on the front left of the aero, for braking if needed. It's a short-pull lever with long pull v-brakes, but works since my rims are very true and pads closely adjusted, and I like the additional leverage and braking power.