I have very limited data, just from what son told me last year. Son played at mid-D1 for 3 years. During that time there were 6-8 walk-on. None of them made it past the first cut. I know of at least 2 of them who were "all-league" from high school. A personal friend of ours has a son who wanted to go to a private D3 school. School wanted him for baseball real bad. Only problem is that even with academic money and some grants, parents would have to pony up around $30K/year, which was too expensive. The son went to a mid-D1 as a preferred walk-on. He made the team, pitched 2 innings in 2 games, end of story. Following year HC made him redshirt. Next year he was cut, finished out the semester, transferred to JC for a semester. 2017 transferred to a very competitive JUCO baseball program, has done so-so. Now talks about going back east to lower D1 program for 2018/2019. In my mind he is spending just as much, if not more, now than what it would have cost to go to the private D3. Go to where you will get a good education and some baseball love that fits your son.