silesian,
If you are going to use Sagarin, use Sagarin, not some formulation you made on the back of a napkin. Sagarin has the SEC as a better conference, but the mean is less than half a point. This means that Sagarin considers both coferences roughly equal. The difference between the SOS between Kentucky and BYU is only 2.7 points out of around 80, which also isn't a dramatic difference.
If we draft Knight, we need to remember that he isn't a normal 3 pick and would likely have been a mid-lottery selection in a normal draft. Ther is a decent chance that Jimmer will be the better pro as he is the better player right now. Understandibly Knight has a higher possible ceiling, but that may or may not happen. I wouldn't pick either with the 3 pick.