Making two changes

I have two other threads running here as I have tried to sort out food and stool issues with my new 11 month old GRD. I need some help on two issues:

1. The breeder was feeding her once a day (in the AM). I suspect it was due to the fact that she was an active competitor and also had 12 or so dogs. My sense is that moving Mia to twice a day should not be a problem and might make more sense. Is it safe to assume I can just do this by dividing her meal and getting started? Any opinions on once a day feeding?

2. She has had a bought of soft stools since arriving almost two weeks ago. I started her on chicken and rice (and a tbsp of pumpkin) this AM with the hopes of firming things up. However, I have also been researching food and plan to move her to something of a higher quality than the food she arrived with (Purina One Sensitive Systems).

I was going to keep her on the rice and chicken for 2 days and then work her back into kibble. Do I go back to the Purina and start the % change-over to whatever new food I select? Or does this 2 days of bland food allow me to simply switch her to a new food?

Thanks for the help. I appreciate the patience with my re-learning the dog world after 15 years of being without one!