You always cook equal volumes of rice and water, but below a cup, you might require a little bit more water to compensate for rapid evaporation rates at the same cook temperature. I would say 1/2 cup rice + 1/2 cup water + 1 tablespoon of water - try that out and see how it works. The extra tablespoon of water is for evaporation compensation.
For the kebobs, just wait until they turn brown and the skin pulls away from the meat.
