S26 Gold gave my DD horrible reflux and wind so we now us Novalac and she is doing very well on it. Your best option would be to speak to your GP or your maternal health nurse (if there is such a thing where you are from)

With formula its pretty much trial and error though i do know swapping and changing can lead to upset tummys so when you switch stay on the new one for a while and see how bub is doing if there is still no improvement then try another.