Anyone have experience with scaling up rice?

Currently working on a project where we are cooking rice in an oven (steamer) and then we add gelatin and form rice bars.

Issue we’re having is when we scale up the ingredients, like 1000g of rice vs 200g, the rice ends up undercooked in the oven. But if we add a few more minutes we get mushy rice. What’s the best method for making large batches of rice? Also, how would this be feasible for scale-up/how do large co-mans produce tons of consistently cooked rice?