I will take part in a closing argument competition come february. it seems to me that the other 10+ participants will typically come from the so-called 3rd/ 4th tier schools but they have very strong coaches.

have you ever taken part in any such competition? do you have an idea of the general standard of these participants??

Don't look down on those Tier 4 schools too much, I'll blast on you. A school I'm familiar with has 100 national championships and regularly smash the larger schools. But if you are looking for advice check out: http://juryargument.homestead.com/