I would focus more on introducing other foods such as vegetables and meat/fish rather than increasing the rice cereal.
Rice cereal has little in the way of nutrition so although it's giving baby an experience of eating solids there isn't really any other benefit. It's also pretty bland, vegetables, fruits and meat/fish offer more in the way of both nutrition and taste, and allow baby the opportunity to learn the tastes of the meals your family regularly eats.
There are many now who skip rice cereal altogether in preference for other foods, whether puréed or as finger foods.
I would continue to give the breast feed 1 hour before solids, at this age and up to 12 months your baby's primary source of food is milk. The regular milk feed routine will continue for several months yet.
hth