re: Suggestions for recessed lights for kitchen .. thinking of going 4"

We did 4" in our entire house when we built 4 years ago. More of a clean modern look. With LED these days, 4" lights have similar lumen and shine angles to 6" lights. So you don't necessarily need more 4" to get the same lighting as 6". Unless you are going for a super bright look, 4" will be fine. With all the other lighting sources you mention, 6" definitely isn't necessary.