
Hi Jane,
There's no reason why you can't use rice as a bulking agent every day - it's impossible to tell if you're giving her too much as only you know what her body/coat/general physical condition and mental wellbeing are like and, importantly, what proportion of protein you're providing at the same time :) I personally would add a supplement such as SA37 to a diet such as you describe to ensure she is getting enough vitamins and minerals - I'm all for home prepared foods whether cooked or raw but you have to research if all the ingredients you're using are sufficient to ensure an over all healthy, balanced diet.
HTH, regards, Teri :)
ps. have you tried feeding her "Nature Diet" ? It's a complete but moist food and rice based too but everything is worked out for you :P