If you want to drop the point total below 2k I would suggest 1850.  The "world wide war" tournaments used that total and they played out really well.  You only need about 2 hours per round or less depending on scenarios.  I definitely would not go below 1500 points though because it starts limiting alot of armies ability to do cool stuff.

As far as prizes a trophy would be cool but not necessary if it jacks up events costs.  For some reason alot of us warhammer players are cheapskates and after dropping 500 or 800 dollars on a force we back away from a $20 tourny fee?  I don't understand the logic but it happens.

Here are a couple more questions.

1. Is painting required? Will it be judged as part of an overall score?  Or possibly award bonus points for fully painted armies?

2. How is the tournament going to work?  Will it be a straight win/loss or a points based system?

3. Some of us are driving in from far away, how many people showed last year and is there a plan for if more than 20 people show up this year?

I think that's it for now.