T.T.
I would not switch formula throughout the day. i would buy one type and stick to that. babies tummys are still developing and the changing of the formula from morning, noon and night might be harder on his/her tummy to digest.
My daughter was both breast/formula fed because i couldnt produce enough milk for her. At six month she was on only formula.
She went through several types of formula until we found the one that worked for her. We did reg. formula to start with IRON and dha in it. But she kept throwing it up, We tried Gentle Ease but still threw it up. We tried Soy but caused her to have dirreaha.
We then switched to Parents Choice Lactose Free Formula with IRON and DHA in it. WORKED!!!! Turns out our child is Lactose intollerant like her Mama and Grandpa and Great-Grandpa.
Unfortantly she didnt grow out of it and is now on Lactaid Milk.
Try the one you think is best and stick to that one and if it doesnt work out then keep looking until you find the one that your child can digest easily enough and stick to that one.
Good luck and healthy drinking little one!