this is the type of tweaking i am talking about. no more than that ever seems necessary. up or down. at most, .025 u/hr.
but i have read on this site about those who make changes, rather often, in the I:C ratios. mine have been the same for a long time, with the exception of my early morning (breakfast time) ratios, which as of late have needed significant tweaking. ( from 1:10 to 1:6 )