I'm in the process of building my wife's replacement commuter bike (previous got stolen) and I'm trying to set up her cockpit to best fit her style of riding.

Key points:

• Drivetrain is ultra compact 2x8 indexed.

• She previously had Sora brifters with interrupter brake levers.

• While commuting she rides mostly on the tops, but likes more hand positions on ocassional longer rides.

• I have been told: "No DT shifters, no bar end shifters."

• She has small, not-so-strong hands and consequently never brakes from the drops.

• Her other bike is a '73 Gitane TdF with guidonnet brake levers and DT Retrofriction shift levers - she loves it for long rides out of traffic but only tolerates the DT shifters.

Given her preferred commuting riding style, I figure she should be riding and braking in the same hand position: the tops. I offered to build her a flat bar setup and got a very negative response. I offered a "Northroad" style setup and got an equally negative response. I am reluctant to go back to her previous style setup because of the inefficiencies and the complexities of interrupter levers. After talking with my wife, she is interested in thumb shifters on the tops combined with guidonnet brake levers.

Now I am left to decide which thumb levers to use on 23.8 diameter bars. Paul's Thumbies and Velo Orange bar mounts seem to be the only options in that size. I've looked at Sunrace 8s shifters but they are only available in 22.2 Mtn standard. However, the Sunrace come with shifters and can be had for about half the price of the other options that are mounts only! The Sunrace mounts are designed as a solid cast of aluminum - no hinge to open the clamp like the Paul's or VO:



Here's the big question: has anyone successfully modified 22.2-clamp Sunrace thumb shifters to fit 23.8 bars? I can't imagine they can be forced to fit without reaming them out? Is this doable or is it "suck it up" time and get the larger diameter thumb mounts?
Thanks for any advice.