Generally speaking, it's better to spec the cam for 1.5 rockers from the get-go. There are reasons one might need to use 1.6 rockers, like in the case of the SBC roller engine that doesn't play well w/cam lobe lifts higher than 0.354". Higher ratio rockers is one way around that to get more lift w/o causing the dog bone to lose contact w/the roller lifter. Maybe not the best way, but it is an option that costs less than the better aftermarket roller lifters.
The valve train has a few places that you can get into trouble when adding lift, like spring coil bind, retainer to seal or guide boss interference, etc. Most things like this are covered in the Points to check link above.