No need for antes, if that's the goal.I also prefer no ante. However an ante tournament was suggested by several of my players as a way to shake up the nits, who fold the entire 4 hours and then bust out with a min cash and higher placed points. And I don't see anything wrong with shaking up the nits
Just run a progressively-aggressive blinds structure that will weed out the nits by the mid-late levels, then relaxes a bit for the remaining big stacks to finish out playing for glory.
It will actually work *better* than antes for your purposes, and also highly reward early active players who fight to build a stack, vs those who attempt to nurse a shortie into the money.