Hi Pamela,
My advice to you is to consider stopping the rice until he's 6 mo. It's quite hard for LOs to learn to digest it, and starting solids often produces tummy upset and gas until they adjust. Starting early, even a month early can make things even worse. Sleep disturbance is often part of the process.
If you must continue with it, it would be better to do it at the 7am feed so that LO has the entire day to work on getting it out of his system before sleep.