I have found that raising my nock point is all I need to do. I'm currently at 3/4" above and getting good arrow flight. (I do bare shaft, etc)
On a side note, when I switched to 3 under, last year, I decided to only shoot 3 under for 30 days to make a fair judgement on wanting to continue that way.
The 1st week my shooting improved. 2nd week, hit a slump and I disliked 3 under but I stuck with it. After that, it became clear to me that I was shooting better 3 under.
Almost a year later now and I'm happy I made the switch. Have fun with it.