It sounds like a re-buy format would be best for you. For the first 2 hours, players can re-buy if they have chips less than or equal to the original stack. This way the stacks will not start too deep, and people can only re-buy when they are low on chips. It also stimulates action and builds your prize pool as well. Once the two hours are up, no more re-buys allowed.
At this time there is usually a break where players can purchase a one time "add-on" to their chips, which is almost always a little more than the original buy-in chip amount. I have seen this be MUCH more though, adding 3X-5X the re-buy chip amount at the add-on period. It's up to you how many chips you want to allow.
You also will want to decide how often the blinds will go up and by how much. This is a great way to get people up and out of your house if the game is running long. :) As the blinds go up, and players can no longer re-buy, people will start quickly dropping from the tourny.
Sorry if you already know all this stuff, but I figured I should explain it in case anyone else needs the info too. :)
Buy-in: $400 Player receives (for example) 1000 chips
Re-Buy: $400 Players can re-buy if chip amount is 1000 or less (you
can decide if you want to let them do a "double re-buy" where they pay
twice the rebuy and get (in this example) 2000 chips.)
Re-Buy Period: 2 hours After the re-buy period ends, no more re-buy's
will be allowed.
Add-on: $400 One add-on of 1750 chips is available during the break
after the re-buy period ends.
Hope this helps. Good Luck. :)