I've read that for SI1 diamonds, inclusions may be visible to naked eye, but I've also read that it may be ok to sacrifice a bit on color and clarity for smaller diamonds. Should I include SI1 diamonds in my search or just move up to VS2 to be safe?
I am in this same process of looking at roughly the same size diamonds. I can tell you that the vendors that you will see on this site recommended such as whiteflash, good old gold, enchanted diamonds, James Allen, and Brian Gavin will either already tell you in the search results whether a diamond is eye clean or will be happy to check and verify for you.
I have asked several through their online chat functions to check on diamonds for me in the last couple days. As Niel indicated, most seem to be eye clean. I will say that I have had 1 come back as not eye clean after review by the person helping at James Allen and several on the various websites are listed as not being eye clean. So you do need to ask if you care about it being eye clean.