I would use a WYK 16-1 Works great on a Hond GX31. It has dual needles, no primer bulb, and will run off of intake manifold pulse. I have found if you are carefull, a new notch can be made with a Dremel to unload the return spring tension on rotary Walbro carbs . Don't screw up the mating surface.
Most of the other Walbro rotary carbs have a idle adjustment in the center of the bellcrank on top. You may have to carefully dig out a potting material to get to it or pop off a plastic plug. If you also drill out the main jet carefully they work ok.
motorhd