Needs to be 8 speed, but thanks for the suggestion. IRD is one of the most expensive options.

I've done some testing with the steel bar and realized it might be more challenging than I thought to get the Sunrace shifters on. They are designed for straight bars, not drops. It might be impossible to get them around bends which tend to be ovalized. The Velo Orange mounts are hinged - perfect for such an application. I tried to mount some old MTB brake levers and they did NOT want to go on the bars.

A bendable steel clamp would be ideal - just like what is used on the brake levers. I wonder if SIS levers could be mounted to those cheap 7s shifters? I will have to investigate further...