my pediatrician has said that the nestle formulas are NOT as good as the Similac and Enfamil brands - so i personally would stay away from them....
as far as digestion - my neice had a VERY severe case of reflux (so bad that she medically qualified to have surgery to correct the problem before she was six months old) and instead of doing that my sister in law and her pediatrician (which is also my pediatrician) created a diet change that helped sustain her until she grew out of the reflux.
They mixed cereal into her bottle. they also put her on Nutramegen ( i think its made my Enfamil but its that or Similac) its VERY expensive - but its the best for digestive disorders. and yes at 5 weeks old you can give them cereal- my neice was younger than that.
Try it - or at least run it by your pediatrican and/or get a second pediatric opinion. Let us know and God Bless!