As hinted earlier, a good way to deal with the rice is to cook it to a mush in order to gelatinise the starches then, when it cools down to about 74 degrees, stir in half a kilo of your crushed base malt and start stirring. It will start off very thick then suddenly loosen up to a runny soup as the Alpha Amylase in the base malt zaps the starch and turns it into dextrins. This is similar to the cereal mash that American brewers do when making adjunct-heavy beers such as Budweiser.
Then you can tip the whole thing into your main mash to finish converting everything at your chosen mash temperature.
You can also do the same thing with Polenta, a fraction of the cost of flaked maize if you buy it from an Asian supermarket.
Remember to take the original rice cooking water out of your total allowance of water for the entire mash.