See, this is why I like this forum. Some things I wouldn't have thought of...
The tournament will be held at my facility, so condition of the tables, time for play will be all up to me.
You guys brought up some great points in regards to time...so it looks like a single elimination would be the way to go. ...
Here's an alternative form of single elimination that is flexible enough to fit how ever many show up. You could call it "mini-qualifiers with buy-back."
Suppose you have a two-day tourney, Saturday and Sunday.
Charge $5 or $10 for entry. As soon as you have 8 people in the room on Saturday, draw into two groups of four. Each group plays single elimination to a short race, like 3 or 4 if they are relatively weak players. Finish each group, so once a group starts it finishes as soon as possible. The winner of each group is qualified for the 16-player "main tournament" and is told to come back, for example, at 3PM on Sunday. All the players who lose and anyone new who walks in the door can get back in for another $5 or $10.
You could run the qualifiers as long as you like but you probably want to announce "last sign-ups" when it looks like it will be hard to form a full group. If you still have a lot of interest and/or new players at 10 PM on Saturday, and things are going to run too late, you could announce a last set of 4 qualifiers on Sunday morning (if that fits in with your finals schedule).
This format is very flexible for the players. If someone gets knocked out and it's dinner time, he can go have dinner and come back and sign up again when he feels like it. If someone keeps getting knocked out and wants to enter 5 times that's OK. If someone can't get there until 4PM on Saturday, that's fine too and he probably will have time to enter twice. If someone shows up at 10 PM on Saturday night, you can probably squeeze him in.
The "main tournament" is a regular single elimination. The length can be adjusted according to how long the matches have been taking, but warn the players about the possible changes. I like to seed the players who qualify first into the bracket according to the standard seeding order but that's not necessary.
If you have half-hour matches (race to 3 or 4?) you can handle 6 entries per hour on average. With 11 hours of play on Saturday, that gives 64 entries and 16 people qualified for Sunday. You can probably get 64 entries from 30 actual bodies, especially if the matches are fast and cheap.
If you wanted to, you could run some qualifiers on Friday night for the locals/regulars. You could also finish in one day if you had fewer players or the matches were shorter.
Good luck.
(P.S. My sister-in-law is from Cobleskill and I used to live in Hamilton.)