I normally try to take 3 or 4 and take two walkons for the rest .. Redshirt one of the 4.
I mean.. You can recruit JUCOs and transfers next season and take more walk ons in this season, both are viable. So it just depends.
But for me, I like to try to get 3 spots per year (+/- 1).. So I wouldn't want 6. But that is just me.