I've blended short and long grain rice without problems.yes, I did adjust water volumes, but left the rice to do it's own thing during the cooking. Worked fine. The result is not as visually pleasing with disparate visible lengths, but this is minor. Ming Tsai uses a white and brown rice blend at his restaurants. https://www.ming.com/food-and-wine/recipes/simply-ming-season-9/house-steamed-rice.htm though I don't know if it's rice of different length types.