Mayer is a much better blocker but athletically a little more limited and Kincaid has better hands. Knox was strictly an in-line blocker in college and can break out for some big plays and get open in the endzone. Knox will be the Y, take advantage of mismatches and get his catches while Kincaid will be the F (as per Beane on McAfee). What is F? F is a move tight end. Here's an article about it for those of you unfamiliar. F is basically a large slot receiver who gets moved around the field to create mismatches.
https://www.espn.com/blog/afcsouth/post/_/id/39454/what-is-the-f